Data Sheet

D224ATLVDSC

March 25, 1999

RC224ATL/224ATLV

EmbeddedModem Family

The new Conexant RC224ATL utilizes a new integrated data pump/controller to allow
the device to directly connect to host processors that are 3.3 V I/O capable. The codec
used in the new part is the same as the codec used in the existing RC224ATL. The
new device is form, fit, and function compatible with the existing device. This means
there are no hardware and software differences between the existing and the new part,
with one exception. The 3.3 V I/O capable part incorporates 3.3 V compatible digital
I/O buffers, hence requiring 3.3 V digital supply instead of 5 V digital supply.

In addition, unlike the current version of RC224ATL, the new part provides both

data and fax capabilities.

Data modes, controlled by an industry standard 2400 AT command set, can

transmit and receive up to 2400 bps.

Fax modes, controlled by a built-in EIA-578 Class 1 command interface, provide

Group 3 transmit and receive functions.

Functional Block Diagram

V.24

EIA-232-D

Interface

Modem

Data Pump

Modem

Controller

Crystal

Telephone

Line

Interface

Modem

LED

Indictors

Optional

NVRAM

Optional
Speaker

Distinguishing Features

Data modes
CCITT V.22 bis (2400 bps), V.22

(1200 bps)

Bell 212A (1200 bps) and 103

(300 bps)

Enhanced AT commands

Group 3 fax modes
V.29 (9600/7200 bps) transmit
V.27 ter (4800/2400 bps)

transmit and receive

V.21 Channel 2 (300 bps)

transmit and receive

EIA-578 Service Class 1 commands

V.42/MNP2-4 and V.42 bis/MNP 5
can be supported through host
software without additional hardware

Data/fax discriminator and auto
answering

Communications software
compatible

Integrated call progress and dialing

No external microcomputer or
memory required

Parallel or serial asynchronous DTE
interface

A/A1 relay control

NVRAM interface allows storage of
two user configurations and four
36-digit dial strings

Automatic adaptive/fixed
compromise equalization

Programmable sleep mode and
wake-up

Full-duplex data mode test
capabilities: Analog loop, local digital
loop, and remote digital loop

Half-duplex fax mode test capabilities

Automatic format/speed sensing

Low power consumption (typical)
Operating: 100 mW
Sleep--Idle: 25 mW
Sleep--Stop: 5 mW

Single +5 V power supply or Dual
+ 3.3 VDD and + 5 VAA power
supplies

Package options:
68-pin plastic leaded chip carrier

(PLCC)

100-pin plastic quad flat pack

(PQFP)

D224ATLVDSC

Conexant

Information provided by Conexant Systems, Inc. (Conexant) is believed to be accurate and reliable. However, no responsibility is
assumed by Conexant for its use, nor any infringement of patents or other rights of third parties which may result from its use. No
license is granted by implication or otherwise under any patent rights of Conexant other than for circuitry embodied in Conexant
products. Conexant reserves the right to change circuitry at any time without notice. This document is subject to change without
notice.

Conexant and "What's Next in Communications Technologies" are trademarks of Conexant Systems, Inc.

Product names or services listed in this publication are for identification purposes only, and may be trademarks or registered
trademarks of their respective companies. All other marks mentioned herein are the property of their respective holders.

Reader Response: To improve the quality of our publications, we welcome your feedback. Please send comments or
suggestions via e-mail to

Conexant Reader Response@conexant.com

. Sorry, we can't answer your technical

questions at this address. Please contact your local Conexant

sales office

or local field applications engineer if you

have technical questions.

Ordering Information

Replacement Matrix

Marketing

Number

Manufacturing

Number

DSP Die

Number

I/O & VCC

VAA/Codec

Package

RC224ATL

R6781-11

L2501

68 PLCC

RC224ATL

R6781-12

L2501

100 PQFP

RC224ATL

R6781-13

L2503

68 PLCC

RC224ATL

R6781-14

L2503

100 PQFP

RC224ATLV

R6781-21

L2531

68 PLCC

RC224ATLV

R6781-22

L2531

100 PQFP

Marketing

Number

Manufacturing

Number

Package

Replaces

RC224ATL

R6781-11

68 PLCC

RC224ATL/V (R6641-14), RC224ATL (R6641-15),

RC224ATL/VN (R6641-16), RC224ATLN (R6641-17),
RC224ATL/VE (R6641-24), RC224ATLE (R6641-25)

RC224ATL

R6781-12

100 PQFP

RC224ATL/V (R6641-18), RC224ATL (R6641-19),
RC224ATL/VN (R6641-20), RC224ATLN (R6641-21),
RC224ATL/VE (R6641-26), RC224ATLE (R6641-27)

RC224ATL

R6781-13

68 PLCC

RC224ATL/VN (R6641-36), RC224ATL/V
(R6641-37), RC224ATLN (R6641-38), RC224ATL
(R6641-39)

RC224ATL

R6781-14

100 PQFP

RC224ATL/VN (R6641-40), RC224ATATL/V
(R6641-41), RC224ATL (R6641-43)

RC224ATLV

R6781-21

68 PLCC

N/A: New 3.3 V Digital I/O

RC224ATLV

R6781-22

100 PQFP

N/A: New 3.3 V Digital I/O

D224ATLVDSC

Conexant

iii

Table of Contents

List of Figures

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

List of Tables

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

1.0

Functional Description

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.1

Overview

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.2

Technical Specifications

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.2.1

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-1

1.2.2

Configurations and Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-2

1.2.3

Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-3

1.2.3.1

Data Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-3

1.2.3.2

Fax Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-3

1.2.4

Data/Fax Auto Answering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-3

1.2.5

Data Modulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-3

1.2.6

Equalization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-3

1.2.7

Scrambler/Descrambler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-3

1.2.8

Transmit Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-4

1.2.9

Transmit Tones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-4

1.2.10

Receive Level. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-4

1.2.11

Receiver Tracking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-4

1.2.12

Low Power Sleep Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-5

2.0

Hardware Interface

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

2.1

Hardware Interface

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

2.1.1

Parallel Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2-6

2.1.2

Serial/Indicator Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2-12

2.1.3

Speaker Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2-12

2.1.4

Line Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2-12

2.2

Additional Information

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12

Table of Contents

RC224ATL/224ATLV

EmbeddedModem Family

Conexant

D224ATLVDSC

3.0

Pin Descriptions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

4.0

AT Commands

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

5.0

S Registers

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

6.0

Operation

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

6.1

Data Modes

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

6.1.1

Data Mode Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-1

6.1.2

Data Modem Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-1

6.1.3

Call Origination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-2

6.1.4

Call Answering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-2

6.1.5

Call Termination. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-2

6.2

Fax Modes

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

6.2.1

Fax Mode Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-3

6.2.2

Fax Mode Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-3

6.2.3

Fax Origination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-3

6.2.4

Fax Answering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-3

6.2.5

Fax Data Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-4

6.2.6

Fax Data Reception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-4

6.2.7

Fax Control Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-4

6.2.8

Fax Control Reception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-5

6.2.9

Fax I/O Processing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-5

6.3

Fax Enhanced Flow Control

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7

6.3.1

Parallel/Serial Interface Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-7

6.3.2

Fax V.42 Buffer Sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-7

6.3.3

DTE Flow Control Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-8

6.4

Data/Fax Auto Answering

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8

6.5

Call Progress

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12

6.5.1

Call Progress Algorithms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-12

6.5.2

Ring Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-13

7.0

Electrical/Mechanical Specifications

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

7.1

Interfacing the RC224ATLV

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

7.2

Environmental Requirements

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

7.3

Interface Timing and Waveforms

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2

Appendix A: RC224ATF Modem Designs

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

A.1

68-Pin PLCC Design for Serial Interface

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

A.2

68-Pin PLCC Design for Parallel Interface

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-6

Appendix B: Acronyms/Abbreviations

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

RC224ATL/224ATLV

List of Figures

EmbeddedModem Family

D224ATLVDSC

Conexant

List of Figures

Figure 2-1.

RC224ATLV Signals--Parallel Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Figure 2-2.

RC224ATLV Signals--Serial Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Figure 3-1.

68-Pin PLCC Package--Serial. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Figure 3-2.

68-Pin PLCC Package--Parallel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Figure 3-3.

100-Pin PQFP Package--Serial. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Figure 3-4.

100-Pin PQFP Package--Parallel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Figure 3-5.

NVRAM Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20

Figure 7-1.

Timing Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

Figure 7-2.

68-Pin PLCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7

Figure 7-3.

100-Pin PQFP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-9

Figure A-1.

Serial Interface Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2

Figure A-2.

Serial Interface Design DAA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3

Figure A-3.

Parallel Interface Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-7

Figure A-4.

Parallel Interface Design DAA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-8

RC224ATL/224ATLV

List of Tables

EmbeddedModem Family

D224ATLVDSC

Conexant

vii

List of Tables

Table 1-1.

Configurations and Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

Table 1-2.

Data Rates vs. Connection Modem Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1- 3

Table 1-3.

Dial Digits/Tone Pairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

Table 1-4.

Current and Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

Table 2-1.

Parallel Interface Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Table 2-2.

Programmable Baud Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12

Table 3-1.

RC224ATL/224ATLV 68-Pin PLCC Pin Assignments--Serial Mode . . . . . . . . . . . . . . . . . . . 3-5

Table 3-2.

RC224ATLV 68-Pin PLCC Pin Assignments--Parallel Mode. . . . . . . . . . . . . . . . . . . . . . . . . 3-6

Table 3-3.

RC224ATL/224ATLV 100-Pin PQFP Pin Assignments--Serial . . . . . . . . . . . . . . . . . . . . . . . 3-7

Table 3-4.

RC224ATL/224ATLV 100-Pin PQFP Pin Assignments--Parallel . . . . . . . . . . . . . . . . . . . . . 3-11

Table 3-5.

Hardware Interface Signal Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15

Table 4-1.

Result Codes and Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Table 4-2.

AT Command Set Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Table 4-3.

Fax Command Set Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

Table 5-1.

S Register Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Table 5-2.

S Register Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

Table 6-1.

Data Rate Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

Table 6-2.

Terminal Called by a 1200 bps Data Modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10

Table 6-3.

Terminal Called by a Fax Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11

Table 6-4.

Tone Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12

Table 6-5.

Fax Class 1 Calling Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13

Table 6-6.

Fax Class 1 Answering Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15

Table 7-1.

Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

Table 7-2.

TimingHost Bus Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2

Table 7-3.

Current and Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4

Table 7-4.

Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4

Table 7-5.

Digital Interface Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

Table 7-6.

Analog Interface Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

Table 7-7.

68-Pin PLCC Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8

Table 7-8.

100-Pin PQFP Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-10

Table A-1.

Serial Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4

Table A-2.

Parallel Billing Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-9

D224ATLVDSC

Conexant

1-1

1.0 Functional Description

1.1 Overview

The Conexant RC224ATLV is a combination V.22 bis data and Group 3 fax
CMOS modem in a single VLSI package and is identical to the RC224ATLV. The
RC224ATLV integrated data/fax modem is available in either a 68-pin plastic
leaded chip carrier (PLCC) or a 100-pin plastic quad flat pack (PQFP).

Full error correction (V.42 LAPM, MNP2-4) and data compression (V.42 bis,

MNP 5) capabilities can be supported in the RC224ATLV using the host
communication software.

The modem has a selectable parallel or serial interface to the host data

terminal equipment (DTE). When parallel mode is selected, a 16C450-compatible
interface allows direct connection to a notebook, laptop, or PC-compatible bus
without an external universal asynchronous receive/transmit (UART). When
serial mode is selected, a CCITT V.24 logic-compatible interface with transistor to
transistor logic (TTL) levels is supplied along with indicator outputs.

1.2 Technical Specifications

1.2.1 General

The RC224ATLV modem is a full-featured, self-contained data/fax solution. No
external microcontroller for data or fax control functions is required. Dialing, call
progress, and telephone line interface functions are fully supported and controlled
through the AT command set.

Data modes perform complete handshake and data rate negotiations. All tone

and pattern detection required by the applicable CCITT or Bell standard are
supported.

Fax modes support Group 3 fax requirements. Fax data and fax control (V.21

300 bps), performed by the modem, are controlled and monitored through the fax
EIA-578 Class 1 command interface. Full HDLC formatting, flag
insertion/deletion, and CRC generation/checking is provided.

Both transmit and receive fax data is buffered within the modem. Fax data

transfer to and from the DTE is flow controlled by X-on/X-off.

1.0 Functional Description

RC224ATL/224ATLV

1.2 Technical Specifications

EmbeddedModem Family

1-2

Conexant

D224ATLVDSC

1.2.2 Configurations and Rates

The supported modem configurations and signaling rates are listed in

Table 1-1

In data modes with serial interface selected, DTE rate offsets of + 1%, 2.5% are
accommodated by adding/deleting stop bits as required. In fax modes, the DTE
rate is 19,200 bps.

Table 1-1. Configurations and Rates

Configuration

Modulation

Transmitter Carrier

Frequency (Hz)

0.01%

Data Rate

(bps)

Baud

(Symbols/Sec.)

Bits Per

Symbol

Constellation

Points

Data Mode

V.22 bis
V.22
Bell 212A
Bell 103

QAM
DPSK
DPSK
FSK

Answer
2400
2400
2400
2225 M
2025 S

Originate
1200
1200
1200
1270 M
1070 S

2400
1200
1200

300

600
600
600
300

4
2
2
1

4
4
1

Fax Mode

V.29

V.27 ter

V.21

QAM
QAM
DPSK
DPSK
FSK

Receive
N/A
N/A
1800
1800
1650 M
1850 S

Transmit
1700
1700
1800
1800
1650 M
1850 S

9600
7200
4800
2400

300

2400
2400
1600
1200

300

4
3
3
2
1

8
8
4
1

Legend:

QAM

Quadrature Amplitude Modulation

DPSK

Differential Phase Shift Keying

FSK

Frequency Shift Keying

Mark condition

Space Condition

N/A

Not Applicable

RC224ATL/224ATLV

1.0 Functional Description

EmbeddedModem Family

1.2 Technical Specifications

D224ATLVDSC

Conexant

1-3

1.2.3 Operation

Modem operation is controlled by AT commands, fax service class 1 commands,
and supporting S registers.

1.2.3.1 Data Modes

Data rate selection is determined by the speed of the originating and answering
modems, as defined in

Table 1-2

1.2.3.2 Fax Modes

Fax modes are negotiated as defined in T.30 and are implemented by AT+F
commands. The AT+FCLASS=1 command causes entry into the fax mode from
the data mode. Most other fax class 1 commands, which start with the AT+F
prefix, are valid only in the fax mode. All data commands are valid in the fax
mode except A/, On, &Tn, and the escape sequence (+++). The AT+FCLASS=0
command terminates the fax mode and causes entry into the data mode.

1.2.4 Data/Fax Auto Answering

The modem can automatically determine if the incoming call is from a data or fax
modem, make the appropriate connection, and inform the DTE of the connection
type.

1.2.5 Data Modulation

The data modulation conforms to V.29, V.27 ter, V.22 bis, V.22, V.21, Bell 212A,
or Bell 103, depending on the selected configuration. Transmitter and receiver
spectrum shaping is provided in accordance with the applicable standard.

1.2.6 Equalization

Automatic adaptive equalization and fixed compromised equalization are
provided to compensate for line distortions and to minimize the effects of
intersymbol interference.

1.2.7 Scrambler/Descrambler

The modem incorporates a self-synchronizing scrambler/descrambler, which
satisfies the applicable CCITT or Bell requirements.

Table 1-2. Data Rates vs. Connection Modem Rate

Originate Modem Rate

(bps)

Connect Speed Based on Answer Modem Rate (bps)

300

1200

2400

300

1200

300

1200

2400

300

1200

2400

1.0 Functional Description

RC224ATL/224ATLV

1.2 Technical Specifications

EmbeddedModem Family

1-4

Conexant

D224ATLVDSC

1.2.8 Transmit Level

The transmit level is 10 dBm

1 dB (at TIP and RING) and can be obtained

using the circuits shown in Appendix A. Carrier and dual tone multi-frequency
(DTMF) transmit levels can be further attenuated using AT%Ln + AT%Dn
commands, respectively. If a higher transmit level is required, an external op amp
can be added.

1.2.9 Transmit Tones

Answer Tone

An answer tone of 2100 Hz (V.22 bis, V.22, or T.30) or 2225 Hz (Bell 212A or
103) is generated.

Guard Tone

An 1800 Hz guard tone can be generated in all data modes.

Calling Tone

An 1100 Hz (0.5 seconds on, 3 seconds off) calling tone (T.30) is generated in the
originate fax mode.

1.2.10 Receive Level

The receiver satisfies performance requirements for a received signal from
9 dBm to 43 dBm. The carrier detect is ON at 43 dBm and OFF at 48 dBm
with a minimum of 2 dB hysteresis.

1.2.11 Receiver Tracking

The modem can accommodate carrier frequency offset up to

7 Hz, and a

transmit timing error of

0.01% (V.22 bis or V.27 ter) or

0.02% (V.22 or Bell

212A).

DTMF Dialing

Standard DTMF tones (digits 0-9, A, B, C, D, *, and #) or pulses (digits 0-9) can
be generated. Refer to

Table 1-3

Ring Detection

RING signal is detected from valid high to low transitions on the RING input line
at frequencies of 15.3 Hz to 63 Hz. A RING is valid if the RING ON time is
greater than 0.125 seconds and is followed by a RING OFF time greater than 0.5
seconds.

Table 1-3. Dial Digits/Tone Pairs (1 of 2)

Dial Digit

Tone 1

Frequency (Hz)

Tone 2

Frequency (Hz)

941

1336

697

1209

697

1336

697

1477

770

1209

770

1336

RC224ATL/224ATLV

1.0 Functional Description

EmbeddedModem Family

1.2 Technical Specifications

D224ATLVDSC

Conexant

1-5

1.2.12 Low Power Sleep Mode

To conserve power, the RC224ATLV has two selectable sleep (power-down)
modes Idle and Stop. If enabled by the IDLEN0 and IDLN1 inputs, the selective
sleep mode is entered whenever the modem is active. The sleep mode indicator
output, SLEEP, is provided to allow external circuits to be powered down when
the modem is in Idle or Stop mode.

The Idle mode allows reduced power consumption with automatic recovery

without additional circuitry. If Idle mode is selected, the modem exits Idle mode
and returns to full operation whenever a ring signal occurs, the DTE writes to the
modem (parallel interface), or WAKEUP input, normally tied to DTR or TXD, is
asserted (serial interface).

The Stop mode further reduces power consumption, as defined in

Table 1-4

770

1477

852

1209

852

1336

852

1477

941

1209

941

1477

697

1633

770

1633

852

1633

941

1633

Table 1-3. Dial Digits/Tone Pairs (2 of 2)

Dial Digit

Tone 1

Frequency (Hz)

Tone 2

Frequency (Hz)

Table 1-4. Current and Power Requirements

Mode

Current (ID)

Power (PD)

Typical

Current @ 25

Maximum Current

@ 0

Typical

Power @ 25

Maximum

Power @ 0

Operating

21 mA

22 mA

100 mW

110 mW

Sleep

Idle

5 mA

6 mA

25 mW

30 mW

Sleep

Stop

1 mA

5 mW

NOTE(S):

1. Test conditions: VDD = 5.0 V

for typical values; VDD = 5.25 V

for maximum values.

2. Test conditions: VDD = 3.3 V

for typical values; VDD = 3.6 V

for maximum values.

2.0 Hardware Interface

RC224ATL/224ATLV

EmbeddedModem Family

2-4

Conexant

D224ATLVDSC

The parallel interface registers are identified in

Table 2-1

Table 2-1. Parallel Interface Registers (1 of 2)

Register

Number

Register

Name

Bit Number

Scratch
Register
(SCR)

Scratch Register

Modem
Status
Register
(MSR)

Data
Carrier
Detect
(DCD)

Ring
Indicator
(RI)

Data Set
Ready
(DSR)

Clear to
Send (CTS)

Delta Data
Carrier
Detect
(DDCD)

Trailing
Edge of
Ring
Indicator
(TERI)

Delta Data
Set Ready
(DDSR)

Delta Clear
to Send
(DCTS)

Line Status
Register
(LSR)

Transmitter
Empty
(TEMT)

Transmitter
Holding
Register
(THRE)

Break
Interrupt
(BI)

Framing
Error (FE)

Parity Error
(PE)

Overrun
Error (OE)

Data Ready
(DR)

Modem
Control
Register
(MCR)

Local
Loopback

Out 2

Out 1

Request to
Send (RTS)

Data
Terminal
Ready
(DTR)

Line
Control
Register
(LCR)

Divisor
Latch
Access Bit
(DLAB)

Set Break
(SB)

Stick Parity
(SP)

Even Parity
Select
(EPS)

Parity
Enable
(PEN)

Number of
Stop Bits
(STB)

Word
Length
Select Bit 1
(WLS1)

Word
Length
Select Bit 0
(WLS0)

Interrupt
Identify
Register
(IIR) (Read
Only)

Pending
Interrupt ID
Bit 1
(PL1)

Pending
Interrupt ID
Bit 0
(PL0)

0 if
Interrupt
Pending
(IP)

DLAB = 0

Interrupt
Enable
Register
(IER)

Enable
Modem
Status
Interrupt
(EDSSI)

Enable
Receiver
Line Status
Interrupt
(ELSI)

Enable
Transmitter
Holding
Register
Empty
Interrupt
(ETBEI)

Enable
Received
Data
Available
Interrupt
(ERBFI)

DLAB = 0

Transmitter
Holding
Register
(THR)

Transmitter Holding Register (Write Only)

DLAB = 0

Receiver
Buffer
Register
(RBR)

Receiver Buffer Register (Read Only)

2.0 Hardware Interface

RC224ATL/224ATLV

2.1 Hardware Interface

EmbeddedModem Family

2-6

Conexant

D224ATLVDSC

2.1 Hardware Interface

2.1.1 Parallel Interface

A 16450 UART-compatible parallel interface is provided.

Host Bus Interface

Eight data lines, three address lines, and four control lines are supported.

Interrupt Enable Register

(Addr=1, DLAB=0)

The Interrupt Enable Register (IER) enables four types of interrupts that can
separately assert the HINT output. A selected interrupt can be enabled by setting
the corresponding enable bit to a logic 1, or disabled by resetting the
corresponding enable bit to a logic 0. All interrupt sources are disabled by setting
bits 03 to a logic 0. Disabling all interrupts inhibits the Interrupt Identifier
Register (IIR) and inhibits assertion of the HINT output. All other system
functions operate normally, including the setting of the Line Status Register
(LSR) and the Modem Status Register (MSR).

Bits 4-7:

Not used (always logic 0).

EDSSI

Enable Modem Status Interrupt.

When this bit is a logic 1,

it enables assertion of the HINT output whenever bit 0, 1, 2, or
3 in the Modem Status Register (MSR) is a logic 1. When this
bit is a logic 0, it disables assertion of HINT due to setting of
any of these four MSR bits.

ELSI

Enable Receiver Line Status Interrupt.

When this bit is a

logic 1, it enables assertion of the HINT output when any
receiver status bit in the Line Status Register (LSR); i.e., bits
1, 2, 3, or 4, changes state. When this bit is a logic 0, it
disables assertion of HINT due to change of the receiver LSR
bits.

ETBEI

Enable Transmitter Holding Register Empty Interrupt.

When this bit is a logic 1, it enables assertion of the HINT
output when the Transmitter Holding Register Empty (THRE)
bit in the Line Status Register (LSR5) is set to a logic 1. When
this bit is a logic 0, it disables assertion of HINT due to LSR5.

ERBFI

Enable Received Data Available Interrupt.

When this bit is

a logic 1, it enables assertion of the HINT output when
received data is available in the Receiver Buffer; i. e., the Data
Ready bit in the Line Status Register (LSR0) is a logic 1.
When this bit is a logic 0, it disables assertion of HINT due to
the LSR0.

EDSSI

ELSI

ETBEI

ERBFI

RC224ATL/224ATLV

2.0 Hardware Interface

EmbeddedModem Family

2.1 Hardware Interface

D224ATLVDSC

Conexant

2-7

Interrupt Identifier

Register (Addr = 2)

The Interrupt Identifier Register (IIR) identifies the existence and type of
prioritized pending interrupts. Four priority levels are set to assist interrupt
processing in the host.

When addressed during chip-select time, the IIR freezes the highest priority

interrupt pending and acknowledges no other interrupts until the particular
interrupt is serviced by the host.

Bits 3-7:

Not used (always 0).

PL0-1

Highest Priority Pending Interrupt.

These two bits identify

the highest priority pending interrupt.

Priority

Level

Pending Interrupt

(highest)

Receiver Line Status

Receiver Buffer Full

Transmitter Holding Register
Empty

Modem Status

Interrupt Pending

. When this bit is a logic 0, an interrupt is

pending. When this bit is a logic 1, no interrupt is pending.
This bit can be used in a hardwired prioritized or polled
environment to indicate whether an interrupt is pending. If an
interrupt is pending, the IIR contents can be used as a pointer
to the appropriate interrupt service routine in the host.

PL1

PL0

2.0 Hardware Interface

RC224ATL/224ATLV

2.1 Hardware Interface

EmbeddedModem Family

2-8

Conexant

D224ATLVDSC

Line Control Register

(Addr = 3)

The Line Control Register (LCR) specifies the format of the asynchronous data
communications exchange.

DLAB

Divisor Latch Access Bit

. This bit must be set to a logic 1 to

access the Divisor latches of the baud generator during a read
or write operation. It must be reset to a logic 0 to access the
Receiver Buffer, the Transmitter Holding Register, or the
Interrupt Enable Register.

Set Break

. When this bit is set to a logic 1, the transmit data is

forced to the space (logic 0) state. The break is disabled by
setting this bit to a logic 0. The Set Break bit acts only on the
transmit data and has no effect on the serial in logic.

Stick Parity

. When stick parity is selected (LCR5 = 1), parity

is enabled (LCR3 = 1), and even parity is selected (LCR4 = 1),
the parity bit is transmitted and checked by the receiver as a
logic 0. When stick parity is selected (LCR5 = 1), parity is
enabled (LCR3 = 1), and odd parity is selected (LCR4 = 0),
the parity bit is transmitted and checked by the receiver as a
logic 1.

EPS

Even Parity Select

. When parity is enabled (LCR3 = 1), and

Stick Parity (LCR5) is a logic 0, the number of logic 1s
transmitted or checked in the data word bits and parity bit is
either even (LCR4 = 1) or odd (LCR4 = 0).

PEN

Parity Enable

. When bit 3 is a logic 1, a parity bit is

generated in the serial out (transmit) data stream and checked
in the serial in (receive) data stream. The parity bit is located
between the last data bit and the first stop bit.

STB

Number of Stop Bits

. This bit specifies the number of stop

bits in each serial out character. If bit 2 is a logic 0, one stop
bit is generated regardless of word length. If bit 2 is a logic 1
when either a 5-, 6-, 7-, or 8-bit word length is selected, two
stop bits are generated. The serial in logic checks the first stop
bit only regardless of the number of stop bits selected.

WLS0 and WLS1 Word Length Select

. These two bits specify the number of

bits in each serial in or serial out character. The encoding of
bits 0 and 1 is:

Bit 1

Bit 0

Word Length

5 Bits

6 Bits

7 Bits

8 Bits

DLAB

EPS

PEN

STB

WLS1

WLS0

RC224ATL/224ATLV

2.0 Hardware Interface

EmbeddedModem Family

2.1 Hardware Interface

D224ATLVDSC

Conexant

2-9

Modem Control Register

(Addr = 4)

The Modem Control Register (MCR) controls the interface with the modem or
data set.

Bit 5-7:

Not used (always 0).

Local Loopback

. When this bit is set to a logic 1, the

diagnostic mode is selected and the following occurs:

Data written to the Transmit Holding Register will be
looped back to the Receiver Buffer Register.

The four modem control bits (CTS, DSR, RI, and DCD)
are internally connected to the four modem control
outputs (RTS, DTR, OUT1, and OUT2), respectively.

OUT2

Output 2

. When this bit is a logic 1, HINT is enabled. When

this bit is a logic 0, HINT is in the high impedance state.

OUT1

Output 1

. This bit is used in local loopback (see MCR4).

RTS

Request to Send

. This bit controls the Request to Send (RTS)

function. When this bit is a logic 1, RTS is on. When this bit is
a logic 0, RTS is off.

DTR

Data Terminal Ready

. This bit controls the Data Terminal

Ready (DTR) function. When this bit is a logic 1, DTR is on.
When this bit is a logic 0, DTR is off.

OUT2

OUT1

RTS

DTR

2.0 Hardware Interface

RC224ATL/224ATLV

2.1 Hardware Interface

EmbeddedModem Family

2-10

Conexant

D224ATLVDSC

Line Status Register

(Addr = 5)

The LSR, an 8-bit register, provides status information to the host concerning data
transfer.

Bit 7:

This bit is set to logic 0.

TEMT

Transmitter Empty

. This bit is set to a logic 1 whenever the

Transmitter Holding Register (THR) and the Transmitter Shift
Register (TSR) are both empty. It is reset to a logic 0 whenever
either the THR or TSR contains a data character.

THRE

Transmitter Holding Register Empty

. This bit indicates that

the modem is ready to accept a new character for
transmission. In addition, this bit causes the modem to issue
an interrupt to the host when the Transmit Holding Register
Empty Interrupt Enable bit (IIR1) is set to logic 1. The THRE
bit is set to a logic 1 when a character is transferred from the
Transmitter Holding Register into the Transmitter Shift
Register. The bit is reset to logic 0 concurrently with the
loading of the Transmitter Holding Register by the host.

BI Break

Interrupt

. This bit is set to a logic 1 whenever the

received data input is a space (logic 0) for longer than two full
word lengths plus 3 bits. The 81 indicator is reset whenever
the host reads the LSR.

FE Framing

Error

. This bit indicates that the received character

did not have a valid stop bit. Bit 3 is set to a logic 1 whenever
the stop bit following the last data bit or parity bit is detected
as a zero bit. The FE bit is reset to a logic 0 whenever the host
reads the LSR.

Parity Error

. This bit indicates that the received data

character does not have the correct even or odd parity, as
selected by the Even Panty Select bit (LCR4) and the Stick
Parity bit (LCR5). The PE bit is set to a logic 1 upon detection
of parity error and is reset to a logic 0 whenever the host reads
the LSR.

OE Overrun

Error

. This bit indicates that data in the Receiver

Buffer Register was not read by the host before the next
character was transferred into the Receiver Buffer Register,
thereby destroying the previous character. The OE bit is reset
whenever the host reads the LSR.

Data Ready

. This bit is set to a logic 1 whenever a complete

incoming character has been received and transferred into the
Receiver Buffer Register. Bit 0 is reset to a logic 0 when the
host reads the Receiver Buffer Register.

TEMT

THRE

RC224ATL/224ATLV

2.0 Hardware Interface

EmbeddedModem Family

2.1 Hardware Interface

D224ATLVDSC

Conexant

2-11

Modem Status Register

(Addr = 6)

The Modem Status Register (MSR) reports the modem's current state and change
information. Bits 4-7 supply current state, and bits 0-3 supply change
information. The change bits are set to a logic 1 whenever a control input from the
modem changes state from the last MSR read by the host. Bits 0-3 are reset to
logic 0 when the host reads the MSR or upon reset.

Whenever Bits 0,1, 2, or 3 are set to a logic 1, a Modem Status Interrupt is

generated.

DCD

Data Carrier Detect

. This bit indicates the logic state of the

DCD output. If Loopback is selected (MCR4 = 1), this bit
reflects the state of OUT2 in the MCR (MCR3).

Ring Indicator

. This bit indicates the logic state of the RI

output. If Loopback is selected (MCR4 = 1), this bit reflects
the state of OUT1 in the MCR (MCR2).

DSR

Data Set Ready

. This bit indicates the logic state of the DSR

output. If Loopback is selected (MCR4 = 1), this bit reflects
the state of DTR in the MCR (MCR0).

CTS

Clear to Send

. This bit indicates the logic state of the CTS

output. If Loopback is selected (MCR4 = 1), this bit reflects
the state of RTS in the MCR (MCR1).

DDCD

Delta Data Carrier Detect

. This bit is set to a logic 1 when

the DCD bit has changed since the MSR was last read by the
host.

TERI

Trailing Edge of Ring Indicator

. This bit is set to a logic 1

when the RI bit changes from a 1 to a 0 state since the MSR
was last read by the host.

DDSR

Delta Data Set Ready

. This bit is set to a logic I when the

DSR bit has changed state since the MSR was last read by the
host.

DCTS

Delta Clear to Send

. This bit is set to a logic 1 when the CTS

bit has changed state since the MSR was last read by the host.

Receiver Buffer Register

(Addr=0, DLAB=0)

The Receiver Buffer Register (RBR) is a read-only register at location 0 (with
DLAB = 0). Bit 0 is the least significant bit of the data, and is the first bit
received.

Transmitter Holding

Register (Addr=0,

DLAB=0)

The Transmitter Holding Register (THR) is a write-only register at address 0
when DLAB = 0. Bit 0 is the least significant bit and the first bit sent.

DCD

DSR

CTS

DDCD

TERI

DDSR

DCTS

2.0 Hardware Interface

RC224ATL/224ATLV

2.2 Additional Information

EmbeddedModem Family

2-12

Conexant

D224ATLVDSC

Divisor Registers

(Addr=0 and 1, DLAB=1)

The Divisor Latch LS Byte and Divisor Latch MS Byte are two read-write
registers at locations 0 and 1 when DLAB = 1, respectively.

The baud rate is selected by loading each divisor latch with the appropriate

hex value.

Table 2-2

lists the programmable values corresponding to the desired

baud rate.

Scratch Register (SCR)

(Addr = 7)

The Scratchpad Register is a read-write register at location 7. This register is not
used by the DSP and can be used by the host for temporary storage.

2.1.2 Serial/Indicator Interface

A DTE serial interface and indicator outputs are supported.

Serial Interface: An 8-line V.24/EIA-232-D or TTL logic serial interface to
the DTE is supported.

LED Indicator Interface: Four direct connect LED indicator outputs are
supported.

2.1.3 Speaker Interface

A speaker output, controlled by AT or V.25 bis commands, is provided for an
optional OEM-supplied speaker circuit.

2.1.4 Line Interface

The EmbeddedModem connects to the line interface circuitry by means of a
receive analog input, two transmit analog outputs, and a ring signal input.

The EmbeddedModem provides three relay control outputs to the line

interface. These outputs may be used to control relays such as off-hook, A/A1,
and talk/data.

2.2 Additional Information

Additional information is provided in the RC224ATLV Modem Designer's Guide
(Order No. 821).

Table 2-2. Programmable Baud Rates

Divisor Latch (Hex)

Divisor

(Decimal)

Baud Rate

01
00
00
00

60
30

384
192

96
48

300
600

1200
2400

D224ATLVDSC

Conexant

3-1

3.0 Pin Descriptions

The RC224ATLV 68-pin PLCC serial and parallel pinouts are displayed in

Figure 3-1

and

Figure 3-2

, respectively. The 100-pin PQFP serial and parallel

pinout diagrams are displayed in

Figure 3-3

and

Figure 3-4

, respectively.

Figure 3-5

displays NVRAM timing.

RC224ATLV 68-pin PLCC serial and parallel pin assignments are displayed in

Table 3-1

and

Table 3-2

, respectively. The 100-pin serial and parallel pin

assignments are displayed in

Table 3-3

and

Table 3-4

, respectively.

Figure 3-1. 68-Pin PLCC Package

Serial

AAE

DTRL

RXD

RESET

VCC

NVRSK

NC
NC

TXD

DTR

IDLEN1

RAGCO

RADCI

TSTBO

RSTBO
RRSTO

10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26

DGND1
XTLO
XTLI
TEST

SLEEP
SPKR
VAA
MODEI
TSTBI
TRSTI
TDACI
RADCO
RRSTI
NC
RSTBI
NC

60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44

RDI

RCS

REN

RING

IDLEN0

DCDL

CI/

DCD

CTS

DGND2

RXA

RFI

AGCIN

KRE

RAGCI

RC224ATL/224ATLV

3.0 Pin Descriptions

EmbeddedModem Family

D224ATLVDSC

Conexant

3-5

Table 3-1. RC224ATL/224ATLV 68-Pin PLCC Pin Assignments

Serial Mode

Pin

Number

Signal Label

I/O Type

Pin

Number

Signal Label

I/O Type

DCDL

AGCIN

IDLEN0

RING

TLKRELAY

SEREN

AGND

WAKEUP

OHRELAY

NVRCS

NVRDIO

SLEEPI

A/A1

RAGCI

MI TO RAGCO

AAE

DTRL

RSTBI

MI TO RSTBO

RXD

RRSTI

MI TO RRSTO

RESET

RADCO

VCC

TDACI

MI TO TADCO

NVRSK

TRSTI

MI TO TRSTO

TSTBI

MI TO TSTBO

MODEI

MI TO MODEO

TXD

VAA

DTR

SPKR

O(DF)

IDLEN1

SLEEP

RAGCO

MI TO RAGCI

RADCI

MI TO RADCO

TEST

DI 4.7K TO VCC

TSTBO

MI TO TSTBI

XTLI

RSTBO

MI TO RSTBI

XTLO

RRSTO

MI TO RRSTI

DGND1

TRSTO

MI TO TRSTI

DGND2

MODEO

MI TO MODEI

DSR

TDACO

MI TO TDACI

CTS

DCD

TXA2

O (DD)

CI/HS

TXA1

O(DD)

NMI

RXA

I(DA)

RFILO

3.0 Pin Descriptions

RC224ATL/224ATLV

EmbeddedModem Family

3-6

Conexant

D224ATLVDSC

Table 3-2. RC224ATLV 68-Pin PLCC Pin Assignments

Parallel Mode

Pin

Number

Signal Label

I/O Type

Pin

Number

Signal Label

I/O Type

HD6

DIO

AGCIN

HD7

DIO

RING

HRD

TLKRELAY

HWT

AGND

HCS

OHRELAY

NVRCS

HA2

SLEEPI

A/A1

RAGCI

MI TO RAGCO

HA1

HA0

RSTBI

MI TO RSTBO

IDLEN0

NVRSK

RRSTI

MI TO RRSTO

RESET

RADCO

VCC

TDACI

MI TO TADCO

HINT

TRSTI

MI TO TRSTO

HDIS

TSTBI

MI TO TSTBO

MODEI

MI TO MODEO

NVRDIO

DIO

VAA

SPKR

O(DF)

IDLEN1

SLEEP

RAGCO

MI TO RAGCI

RADCI

MI TO RADCO

TEST

4.7k TO VCC

TSTBO

MI TO TSTBI

XTLI

RSTBO

MI TO RSTBI

XTLO

RRSTO

MI TO RRSTI

DGND1

TRSTO

MI TO TRSTI

DGND2

MODEO

MI TO MODEI

HD0

DIO

TDACO

MI TO TDACI

HD1

DIO

HD2

DIO

TXA2

O (DD)

HD3

DIO

TXA1

O(DD)

NMI

RXA

I(DA)

HD4

DIO

RFILO

HD5

DIO

RC224ATL/224ATLV

3.0 Pin Descriptions

EmbeddedModem Family

D224ATLVDSC

Conexant

3-7

Table 3-3. RC224ATL/224ATLV 100-Pin PQFP Pin Assignments

Serial (1 of 4)

Pin Number

Signal Label

I/O Type

(1)

DTR

IDLEN1

RAGCO

(2)

to RAGCI

RADCI

MI to RADCO

TSTBO

MI to TSTBI

(3)

RSTBO

MI to RSTBI

RRSTO

MI to RRSTI

TRSTO

MI to TRSTI

MODEO

MI to MODEI

TDACO

MI to TDACI

SLEEP

DGND

(4)

MODEI

MI to MODEO

VAA

SPKR

O(DF)

AGND

TXA2

O(DD)

TXA1

O(DD)

RXA

I(DA)

RFILO

NOTE(S):

(1)

I/O Types are described in

Figure 7-5, Digital Interface Characteristics

and

Figure 7-6, Analog Interface Characteristics

(2)

MI = Modem Interconnection

(3)

NC = No external connection (may have internal connection, leave pin disconnected
(open)).

(4)

AGND is analog ground and DGND is digital ground.

(5)

Connect to VCC through 4.7 k

(6)

Connect ATL to + 5 VCC, ATLV to + 3 VCC.

3.0 Pin Descriptions

RC224ATL/224ATLV

EmbeddedModem Family

3-8

Conexant

D224ATLVDSC

AGCIN

AGND

TLKRELAY

AGND

OHRELAY

SLEEPI

RAGCI

MI to RAGCO

AGND

RSTBI

MI to RSTBO

RRSTI

MI to RRSTO

RADCO

MI to RADCI

TDACI

MI to TDACO

TRSTI

MI to TRSTO

TSTBI

MI to TSTBO

TEST

(5)

XTLI

Table 3-3. RC224ATL/224ATLV 100-Pin PQFP Pin Assignments

Serial (2 of 4)

Pin Number

Signal Label

I/O Type

(1)

NOTE(S):

(1)

I/O Types are described in

Figure 7-5, Digital Interface Characteristics

and

Figure 7-6, Analog Interface Characteristics

(2)

MI = Modem Interconnection

(3)

NC = No external connection (may have internal connection, leave pin disconnected
(open)).

(4)

AGND is analog ground and DGND is digital ground.

(5)

Connect to VCC through 4.7 k

(6)

Connect ATL to + 5 VCC, ATLV to + 3 VCC.

RC224ATL/224ATLV

3.0 Pin Descriptions

EmbeddedModem Family

D224ATLVDSC

Conexant

3-11

Table 3-4. RC224ATL/224ATLV 100-Pin PQFP Pin Assignments--Parallel (1 of 4)

Pin Number

Signal Label

I/O Type

(1)

IDLEN1

RAGCO

(2)

to RAGCI

RADCI

MI to RADCO

TSTBO

MI to TSTBI

(3)

RSTBO

MI to RSTBI

RRSTO

MI to RRSTI

TRSTO

MI to TRSTI

MODEO

MI to MODEI

TDACO

MI to TDACI

SLEEP

DGND

(4)

MODEI

MI to MODEO

VAA

SPKR

O(DF)

AGND

TXA2

O(DD)

TXA1

O(DD)

RXA

I(DA)

NOTE(S):

(1)

I/O Types are described in

Figure 7-5, Digital Interface Characteristics

and

Figure 7-6, Analog Interface Characteristics

(2)

MI = Modem Interconnection.

(3)

NC = No external connection (may have internal connection, leave pin disconnected
(open)).

(4)

AGND is analog ground and DGND is digital ground.

(5)

Connect to VCC through 4.7 k

(6)

Connect ATL to + 5 VCC, ATLV to + 3 VCC.

3.0 Pin Descriptions

RC224ATL/224ATLV

EmbeddedModem Family

3-12

Conexant

D224ATLVDSC

RFILO

AGCIN

AGND

TLKRELAY

AGND

OHRELAY

SLEEPI

RAGCI

MI to RAGCO

AGND

RSTBI

MI to RSTBO

RRSTI

MI to RRSTO

RADCO

MI to RADCI

TDACI

MI to TDACO

TRSTI

MI to TRSTO

TSTBI

MI to TSTBO

TEST

(5)

Table 3-4. RC224ATL/224ATLV 100-Pin PQFP Pin Assignments--Parallel (2 of 4)

Pin Number

Signal Label

I/O Type

(1)

NOTE(S):

(1)

I/O Types are described in

Figure 7-5, Digital Interface Characteristics

and

Figure 7-6, Analog Interface Characteristics

(2)

MI = Modem Interconnection.

(3)

NC = No external connection (may have internal connection, leave pin disconnected
(open)).

(4)

AGND is analog ground and DGND is digital ground.

(5)

Connect to VCC through 4.7 k

(6)

Connect ATL to + 5 VCC, ATLV to + 3 VCC.

RC224ATL/224ATLV

3.0 Pin Descriptions

EmbeddedModem Family

D224ATLVDSC

Conexant

3-15

Table 3-5. Hardware Interface Signal Definitions (1 of 5)

Label

I/O Type

Signal Name/Description

System Signals

XTLI
XTLO

IE
OE

Crystal/Clock In and Crystal Out. The modem must be connected to an external crystal
circuit consisting of a 16.000312 MHz crystal and two capacitors. Alternatively, XTLI may be
driven with a buffered clock, in which case XTLO should be left open.

RESET

Reset. The active low RESET input resets the internal modem logic. Upon RESET
transitioning from high to low, modem operation returns to the state controlled by factory
default values and stored values in NVRAM. During modem power-on, RESET must be held
low for at least 5 ms after +5 VD and +5 VA operating voltage (see TSVD and +5 VA below) is
attained for the modem top stabilize.

When the serial interface is selected, RESET can be connected to an external RC network

to cause the modem to reset upon power turn on. When the parallel interface is selected,
RESET should be connected to the hose bus reset line.

SEREN

Serial Interface Enable. When the SEREN input is low, serial interface is selected upon reset.
In this case, the serial interface signals should be connected to the V.24 (EIA-232-D) interface
and LED indicators.

VCC
VAA

PWR

Digital Supply. +5 V/3.3V ATLV

5% is required.

Analog Supply. +5 V ±5% is required.

DGND
AGND

GND

Digital and Analog Grounds.

Sleep Mode Signals

IDLEN0
IDLEN1

DI
DI

Idle Enable 0 and Idle Enable 1. Encoded inputs enable or disable the sleep modes as
follows:

IDLEN1

IDLEN0 Mode

Idle mode disabled

Idle mode enabled

Stop mode disabled

Stop mode enabled

If Idle option is enabled, the modem will enter idle mode after 5 seconds of inactivity
(WAKEUP must also be high for the serial interface). The modem will wakeup upon DTE
activity (RXD for parallel mode and low on WAKEUP for serial mode) or the presence of
RING.

If Stop option is selected, the RING input becomes RING (i.e., the RING signal must be

inverted). The modem will enter stop mode after 5 seconds of inactivity (and if WAKEUP is
high for the serial interface). Only a 4 ms or longer pulse on the RING pin can wake up the
modem from stop mode.

SLEEP

Sleep Mode. SLEEP output high indicates the modem is operating in its normal mode.
SLEEP low indicates that the modem is in the sleep mode. The SLEEP output can also be
used to control power to other devices.

SLEEPI

Sleep Mode. SLEEP input low causes the Integrated Analog (IA) to enter low-power sleep
mode.

3.0 Pin Descriptions

RC224ATL/224ATLV

EmbeddedModem Family

3-16

Conexant

D224ATLVDSC

WAKEUP

Wake Up. For serial interfaces only, WAKEUP input low removes the modem from the sleep
mode (if in the sleep mode), or prevents the modem from entering the sleep mode (if not in
the sleep mode). WAKEUP high allows the modem to enter sleep mode after 5 seconds of
modem inactivity. WAKEUP is typically connected to DTR or TXD.

NVRAM Interface

NVRCS

NVRAM Chip Select. NVRCS output high enables the NVRAM.

NVRSK

NVRAM Shift Clock. The NVRSK output is used to shift data to or from the NVRAM.

NVRDIO

DIO

NVRAM Data In/NVRAM Data Out. NVRDIO is a bidirectional signal that carries both the
serial input data from the NVRAM and the serial output data to the NVRAM. Depending on the
specific NVRAM used, a resistor may be required between the NVRAM DO output pin and the
modem NVRDIO bidirectional line. (Refer to

Figure 3-5

and the NVRAM data sheet.)

Speaker Interface

SPKR

O(DF)

Speaker Analog Output. The SPKR output reflects the output of the receive analog signal.
The SPKR output is turned on or off by the Speaker Control Option (Mn command), and the
gain is controlled by the Speaker Volume Option (Ln command). When the speaker is turned
off, the SPKR output is clamped to the voltage at the VC pin. The SPKR output can drive a
load as low as 300

. Typically, the SPKR output is an input to an external LM386 audio

power amplifier.

Asynchronous Serial Interface (Serial Interface Only; SEREN = Low)

RXD

Received Data. The modem presents received serial data to the RXD output pin.

TXD

Transmitted Data. The modem obtains serial data to be transmitted from the TXD pin.

DTR

Data Terminal Ready. DTR input ON (low) indicates that the DTE is ready to operate. DTR
input OFF (high) indicates that the DTE is not ready to operate.

CTS

Clear to Send. In data modes, the CTS output is ON; in fax modes, CTS is optionally used for
flow control.

DSR

Data Set Ready. The DSR output is controlled by the AT&Sn command.

DCD

Data Carrier Detected. The DCD output is controlled by the AT&C command.

CI/HS

Calling Indicator/High Speed Indicator. CI/HS output ON (low) indicates modem connection
at 2400 bps.

Ring Indicator. RI output ON (low) indicates the presence of an ON segment of a ring signal
on the telephone line. (The ring signal cycle is typically 2 seconds ON, 4 seconds OFF.) The
OFF (high) condition of the RI output is maintained during the OFF segment of the ring cycle
(between rings) and at all other times when ringing is not being received.

Serial Indicator Interface (Serial Interface Only; SEREN = Low)

AAE

Auto Answer Enable. AAE output ON (low) indicates that modem auto answer mode has
been enabled with the S0 = command. AAE high indicates auto answer has been disabled.
The AAE output also indicates the status of the RI output.

Modem Ready. MR output ON (low) indicates that the modem is ready; i.e., modem power is
on and a test mode is not selected. In a test mode, the MR output pulses to indicate a test is
in process.

Table 3-5. Hardware Interface Signal Definitions (2 of 5)

Label

I/O Type

Signal Name/Description

RC224ATL/224ATLV

3.0 Pin Descriptions

EmbeddedModem Family

D224ATLVDSC

Conexant

3-17

DCDL

DCD Indicator. The DCDL output is controlled by the AT&C command.

DTRL

DTR Indicator. The DTRL output is controlled by the AT&D command.

Parallel Host Interface (Parallel Interface Only)

When the HWT input signal is connected to the host bus write line, the parallel interface is
selected upon reset. (See

Section 7.3, Interface Timing and Waveforms

for waveform and

timing information.)

The parallel interface emulates a 16C450 UART; (See

Table 2-1, Parallel Interface

Registers

). Parallel interface operation is equivalent to 16C450 operation with CS0 and CS1

inputs high and DISTR, DOSTR, and ADS inputs low. The corresponding RC224ATLV and
16C450 signals are shown below. 16C450 signals that are not required for RC224ATLV host
computer operation are not shown.

16C450 Signal

RC224ATLV Signal

A0 - A2

HA0 - HA2

D0 - D7

HD0 - HD7

MR RESET (Active low)
CS2 HCS
DISTR HWT
DOSTR

HRD

INTRPT

HINT

DDIS HDIS
OUT2

None (Implemented internally in RC224ATLV)

HA0-HA2

HD0-HD7

DIO

Host Bus Address Lines 0-2. During a host read or write operation, signals HA0HA2 select
an internal register. The state of the divisor latch access bit (DLAB) affects the selection of
certain registers.
Host Bus Data Lines 0-7. HD0-HD7 are comprised of eight tri-state I/O lines providing
bidirectional communication between the host and the modem. Data, control words, and
status information are transferred through HD0-HD7.

HCS

Host Bus Chip Select. HCS input low enables reading from or writing to the modem using the
parallel bus.

HRD

Host Bus Read. HRD is an active low read control input. When the modem is selected with
HCS, HRD low allows status or data words to be read from an addressed register.

HWT

Host Bus Write. HWT is an active low write control input. When the modem is selected with
HCS, HWT low allows data or control words to be written to an addressed register.

Table 3-5. Hardware Interface Signal Definitions (3 of 5)

Label

I/O Type

Signal Name/Description

DLAB

HA2

HA1

HA0

Register

Receive Buffer Register (Read),
Transmitter Holding Register (Write)

Interrupt Enable Register

Interrupt Identification Register (Read Only)

Line Control Register

Modem Control Register

Line Status Register (Read Only)

Scratch Register

Divisor Latch Register (Least Significant Byte)

Divisor Latch Register (Most Significant Byte)

3.0 Pin Descriptions

RC224ATL/224ATLV

EmbeddedModem Family

3-18

Conexant

D224ATLVDSC

HDIS

Host Bus Driver Disable. HDIS output is low when the host is reading data from the modem
over the host data bus (both HRD and HCS are low). HDIS is also used to disable the external
transceiver drivers whenever data is not being read from the modem.

HINT

Host Bus Interrupt. HINT output is 16C450-compatible output indicating interrupt status and
is enabled by the OUT2 bit set to a 1 in the Modem Control Register.

Telephone Line Interface

TXA1
TXA2

O(DF)

Transmit Analog 1 and 2. The TXA1 and TXA2 outputs are differential outputs. A 600

telephone coupling transformer may be driven directly without the need for external discrete
buffer amplifiers.

Both TXA1 and TXA2 outputs are turned off when the transmitter is disabled or during

local analog loopback.

RXA

I(DA)

Receive Analog. RXA is a single-ended receive data input from the telephone line interface.

Centerpoint Voltage. A +2.5 VDC centerpoint voltage derived from an internal reference
voltage. The TXA1 and TXA2 outputs are biased at VC.

TLKRELAY

Talk/Data Relay Driver. TLKRELAY is an open drain output which can directly drive a relay
with greater than 360

coil resistance and has "must operate" voltage of no greater than 4.0

VDC. A heavier load, such as an electro-mechanical relay, requires the use of an external
transistor. An external diode should be provided across the relay coil.

The TLKRELAY output is clamped off during power-on reset or the sleep mode. The

TLKRELAY output is activated and deactivated at the same time as the OHRELAY output.

In a typical application, TLKRELAY ON opens the normally closed Talk/Data relay and

disconnects the handset from the telephone line.

OHRELAY

Off-Hook Relay Driver. OHRELAY is an open drain output which can directly drive a relay with
greater than 360

coil resistance and has "must operate" voltage of no greater than 4.0

VDC. A heavier load, such as an electro-mechanical relay, requires the use of an external
transistor. An external diode should be provided across the relay coil.

The OHRELAY output is clamped off during power-on reset or the sleep mode. In a typical

application, OHRELAY ON closes the normally open Off-Hook relay and connects the modem
to the telephone line (off-hook).

RING

Ring Detector. RING is a TTL-compatible input used to indicate to the modem that a 15.3 Hz
to 63 Hz ringing signal is present.

The signal (a 4N35 optoisolator compatible output) into the RING input should not

respond to a voltage less than 40 V

RMS

, 15 Hz to 68 Hz, appearing across TIP and RING with

respect to ground.

A low-going edge on the RING input also removes the modem from the sleep mode.

A/A1

Key Telephone Hold Indicator. A/A1 output low indicates that the telephone line is in use
when used on multi-line key telephones.

Table 3-5. Hardware Interface Signal Definitions (4 of 5)

Label

I/O Type

Signal Name/Description

RC224ATL/224ATLV

3.0 Pin Descriptions

EmbeddedModem Family

D224ATLVDSC

Conexant

3-19

Modem Interconnect

RFILO

Receive Filter Output. RFILO is the output of the internal receive anti-aliasing filter which
must be connected to AGCIN through a 0.1

F, 20%, DC decoupling capacitor. The 1000 pF

capacitor to ground provides noise immunity at low noise levels.

AGCIN

Receive AGC Gain Amplifier Input. See RFILO.

MODEO (DSP),
MODEI (IA)

Mode Control. Direct modem interconnect line.

TDACO (DSP),
TDACI (IA)

Transmitter DAC Signal. Serial digital DAC signal. Direct modem interconnect line.

TSTBO (DSP),
TSTBI (IA)

Transmitter Strobe. 576 kHz digital transmitter timing reference. Direct modem interconnect
line.

TRSTO (DSP),
TRSTI (IA)

Transmitter Reset. 9.6 kHz, 8228.57 Hz, or 7.2 kHz digital transmitter timing reference.
Direct modem interconnect line.

RADCI (DSP),
RADCO (IA)

Receiver ADC Signal. Serial digital ADC signal. Direct modem interconnect line.

RAGCO (DSP),
RAGCI (IA)

Receiver AGC Signal. Serial digital AGC signal. Direct modem interconnect line.

RRSTO (DPS),
RRSTI (IA)

Receiver Reset. 9.6 kHz, 8228.57 Hz, or 7.2 kHz digital receiver timing reference. Direct
modem interconnect line.

RSTBO (DSP),
RSTBI (IA)

Receiver Strobe. 576 kHz digital receiver timing reference. Direct modem interconnect line.

Table 3-5. Hardware Interface Signal Definitions (5 of 5)

Label

I/O Type

Signal Name/Description

D224ATLVDSC

Conexant

4-1

4.0 AT Commands

Each command line must start with the AT prefix and be terminated with a
carriage return (CR). Several commands may be included on one command line.
A command line may contain up to 40 characters, excluding the AT prefix and the
terminating CR. A separator is not required between data commands. A
semicolon (;) separator is required between fax commands.

AT commands are composed of 10-bit ASCII encoded asynchronous

characters. The character format in data mode is 8 data bits with no parity, or 7
data bits with even, odd, or no (two stop bits) parity, at a data rate of 19,200, 2400,
1200, or 300 bps. The character format in fax mode is 8 data bits with no parity at
19,200 bps.

Table 4-1

lists result codes and messages.

Table 4-2

summarizes the AT

command set.

Table 4-3

summarizes the fax command set.

Table 4-1. Result Codes and Messages

Digital Code

Word Code

Meaning

Command line executed without errors

CONNECT

Connection at 300 bps

RING

Ringing signal detected

NO CARRIER

Carrier lost or never present

ERROR

Invalid command, checksum, error in
command line, or command line exceeds 40
characters

CONNECT 1200

Connection at 1200 bps

NO DIALTONE

No dial tone detected

BUSY

Busy signal detected

NO ANSWER

No silence detected when dialing a system not
providing a dial tone

CONNECT 2400

Connection at 2400 bps

+F4

+FCERROR

Fax carrier error

DATA

Connected as data modem during auto answer

FAX

Connected as fax modem during auto answer

4.0 AT Commands

RC224ATL/224ATLV

EmbeddedModem Family

4-2

Conexant

D224ATLVDSC

Table 4-2. AT Command Set Summary (1 of 5)

Command

Function

Default

Parameters/Description

Re-execute command

Answer a call

Command line prefix
Parameters: none

Attention Code. Precedes the command line except for +++
(escape) and A/ (repeat) commands.

Select CCITT or Bell Mode

Parameters: n = 0,1

n = 1

n = 0 Selects CCITT operation at 300 or 1200 bps during Call

Establishment and a subsequent connection.

n = 1 Selects BELL operation at 300 or 1200 bps during Call

Establishment and a subsequent connection.

Carrier control
Parameters: n = 0,1

n = 1

Dial Command. D causes the modem to dial the number which
follows the D in the command line. Valid dial characteristics are 0
to 9, A to D, #, and *. Other valid dial modifier characters are ","
P, R, S=n, T, W, ";", @, and !.

Dial modifier

Command echo
Parameters: n = 0,1

n = 1

n = 0 Disables

command

echo.

n = 1 Enables

command

echo.

On-line character echo option
Parameters: n = 0,1

n = 1

n = 0 Returns

ERROR result code.

n = 1 Returns OK result code.

Disconnect (hang-up)
Parameters: n = 0,1

n = 0

n = 0 Modem on-hook (relay open).
n = 1 Modem off-hook (relay closed).

Identification

Parameters: n = 0,1,2,3

n = 0

n = 0 Reports

product

identification

code.

n = 1 Calculates the ROM checksum.
n = 2 Calculates the ROM checksum and compares it with the

prestored checksum. Reports "OK" if the calculated
checksum equals the prestored checksum or if the
prestored checksum value is FFh; otherwise reports
"ERROR".

n = 3 Reports the firmware version and ROM part number.

Speaker volume
Parameters: n = 0,1,2,3

n = 2

n = 0 Low

volume.

n = 1 Low volume.
n = 2 Medium

volume.

n = 3 High

volume.

Speaker control
Parameters: n = 0,1,2,3

n = 1

n = 0 Speaker is always off.
n = 1 Speaker is on during Call Establishment, but off when

receiving carrier.

n = 2 Speaker is always on.
n = 3 Speaker is on after dialing, until carrier is detected.

Go on-line
Parameters: n = 0,1

n = 0 On-line

state.

n = 1 On-line state with equalizer retrain.

Force pulse dialing

Quiet Result codes control

n = 0

n = 0 Enables result codes to the DTE.
n = 1 Disables result codes to the DTE.

RC224ATL/224ATLV

4.0 AT Commands

EmbeddedModem Family

D224ATLVDSC

Conexant

4-3

Select S register as default
Range: n = 0-27

Establishes S-Register n as the last register accessed.

n = v

Sets S-Register n to the value v.

Reports the value of S-Register n.

Sn =

Parameters: none
Range:

n = 0-27 (register

no.)

x=0-255 (value)

Writes to an S Register. Sr=x sets register "n" to the value "x".
Configuration registers are provided to retain modem
configuration parameters. The contents of these registers can be
modified with this command.

Sn?

Parameters: none
Range: n = 0-27

Reads an S register. Sn? causes the contents stored in register
"n" to be returned.

Force DTMF dialing

Report codes form

n = 1

n = 0 Result code is sent as a digit.
n = 1 Result code is sent as ASCII text.

Extended result codes

n = 4

n = 0 Basic set of result codes 0-4 are enabled. The modem

blind dials and sends the appropriate connect result code
once a satisfactory connection is established. Dial tone
and busy are not recognized.

n = 1 Result codes 0-5 and 10 are enabled. The modem blind

dials and sends the appropriate connect result code once
a satisfactory connection is established. Dial tone and
busy are not recognized.

n = 2 Result codes 0-6 and 10 are enabled; dial tone detected.

The modem waits for a dial tone before dialing, then
sends the appropriate result code once a satisfactory
connection is established. The busy result code is sent if
a busy signal is detected.

n = 3 Result codes 0-5, 7 and 10 are enabled; busy signal

detected; dial tone not detected. The modem blind dials
and sends the appropriate connect result code once a
satisfactory connection is established. The busy result
code is sent if a busy signal is detected.

n = 4 Result codes 0-7 and 10 are enabled; busy signal and

dial tone detected. The modem waits for a dial tone
before dialing, then sends the appropriate result code
once a satisfactory connection is established. The NO
DIALTONE result code is sent if the dial tone is not
detected within 5 seconds. The BUSY result code is sent
if a busy signal is detected.

Long space disconnect

n = 0

n = 0 Disables long space disconnect.
n = 1 Enables long space disconnect.

Soft reset and restore profile

n = 0

n = 0 Soft reset. Restores stored profile 0.
n = 1 Soft reset. Restores stored profile 1.

&Cn

RLSD (DCD) option

n = 0

n = 0 RLSD remains ON at all times.
n = 1 RLSD follows the state of the carrier.

Table 4-2. AT Command Set Summary (2 of 5)

Command

Function

Default

Parameters/Description

4.0 AT Commands

RC224ATL/224ATLV

EmbeddedModem Family

4-4

Conexant

D224ATLVDSC

&Dn

DTR option

n = 0

n = 0 Modem

ignores

DTR.

n = 1 Modem assumes command state when ON-to-OFF

transition is detected on DTR.

n = 2

Modem hangs up, assumes command state and disables
auto-answer upon detecting ON-toOFF transition on
DTR.

n = 3 Modem assumes software reset state upon detecting

ON-to-OFF transition on DTR.

Recall (restore) factory profile

S Registers: S0=1, S1=0, S2=43. S3=13, S4=10, S5=8, S6=0,
S7=30, S8=2, S9=5, S10=14, S11=95, S12=50, S18=0, S25=5,
S26=1

Commands: B1, C1, E1, F1, L2, M1, P, Q0, V1, Y0, X4, &C0, &D0,
&G0, &J0, &M0/&G0, &P0, &R0, &S0, &T4, &X0

&Gn

Select guard tone

n = 0

n = 0 No guard tone.
n = 1 550 Hz guard tone.
n = 2 1800 Hz guard tone.

&Jn

Telephone jack control

n = 0

n = 0 Suitable for RJ11, RJ41S. or RJ45S type phone jack.
n = 1 Suitable for RJ12 or RJ13 type phone jack; the A lead is

connected to A1 lead while the modem is off-hook.

&L0

Dial-up line operation

n = 0

n = 0 Requests

dial-up

operation.

&Mn

Asynchronous mode

n = 0

n = 0 Asynchronous

operation.

n = 1 Reserved
n = 2 Reserved
n = 3 Reserved

&Pn

Pulse dial make/break ratio

n = 0

n = 0 Selects 39%61% make/break ratio at 10 pps.

(USA/Canada)

n = 1 Selects 33%67% make/break ratio at 10 pps. (UK/HK)

&Q0

Asynchronous mode

n = 0

Idle State On-line State
n = 0 Normal Asynchronous
n = 1 Reserved Reserved
n = 2 Reserved Reserved
n = 3 Reserved Reserved

&Sn

DSR override

n = 0

n = 0 DSR will remain ON at all times.
n = 1 DSR will become active after answer tone has been

detected and inactive after the carrier has been lost. DSR
is OFF when the modem is in test mode or idle state.

Table 4-2. AT Command Set Summary (3 of 5)

Command

Function

Default

Parameters/Description

RC224ATL/224ATLV

4.0 AT Commands

EmbeddedModem Family

D224ATLVDSC

Conexant

4-5

&Tn

Test and diagnostic

n = 4

n = 0 Terminates test in progress.
n = 1 Initiates local analog loopback.
n = 2 Returns

ERROR.

n = 3 Initiates

local

digital

loopback.

n = 4 Enables digital loopback acknowledgment from remote

modem for RDL.

n = 5 Disables digital loopback acknowledgment from remote

modem for RDL.

n = 6 Initiates

remote

digital

loopback.

(1)

n = 7 Initiates remote digital loopback with self test.

(1)

n = 8 Initiates local analog loopback with self test.

(1)

Display current configurations

Example:
AT&V
ACTIVE PROFILE:
B0 E1 L1 M1 QO T V1 Y0 &C0 &D0 &G2 &J0 &L0 &P0 &Q0 &R0
&S0 &X0 &Y0
S00:000 S01:000 S02:043 S03:013 S04:010 S05:008 S06:002
S07:030 S08:002 S09:006
S10:014 S12:050 S14:AAH S16:00H S18:000 S21:00H S22:76H
S23:17H S25:005 S26:001 S27:40H
STORED PROFILE 0:
B1 E1 L2 QO V1 X4 Y0 &C0 &D0 &G0 &J0 &L0 &P0 &Q0 &R0
&S0 &X0
S00:000 S14:AAH S18:000 S21:00H S22:76H S23:17H S25:005
S26:001 S27:40H
STORED PROFILE 1:
B1 E1 L2 QO V1 X4 Y0 &C0 &D0 &G0 &J0 &L0 &P0 &Q0 &R0
&S0 &X0
S00:000 S14:AAH S18:000 S21:00H S22:76H S23:17H S25:005
S26:001 S27:40H
TELEPHONE NUMBERS:
&Z0= 5551212
&Z1=
&Z2=
&Z3=

&Wn

Store current configuration

n = 0

Commands: Bn, En, Ln, Mn, P or T, Qn, Vn, Yn, &Cn &Dn, &Gn,
&Jn, &Ln, &Pn, &Qn, &Rn, &Sn &Xn &Yn

Registers: S0, S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S12,
S14, S16, S18, S21, S22, S23, S25, S26, S27

n = 0 Stores active profile in location 0.
n = 1 Stores active profile in location 1.

&X0

Asynchronous data
transmission

n = 0

n = 0 Reserved
n = 1 Reserved
n = 2 Reserved

&Yn

Select default profile

n = 0 The modem will use profile 0 on powerup.
n = 1 The modem will use profile 1 on powerup.

&Zn = x

Store dial string to location n

&Zn = x n = 0 to 3 and x = dial string. (up to 36 characters)

Table 4-2. AT Command Set Summary (4 of 5)

Command

Function

Default

Parameters/Description

RC224ATL/224ATLV

4.0 AT Commands

EmbeddedModem Family

D224ATLVDSC

Conexant

4-7

Table 4-3. Fax Command Set Summary (1 of 2)

Fax Command

Function

Default

Parameters/Description

+FCLASS=n

Service class

n = 0

Select Service Class. +FCLASS=n command sets the active service
class.
+FCLASS=0

Returns to data mode

+FCLASS=1

Fax Class 1

+FCLASS=2

Fax Class 2 (Not supported)

+FCLASS=3

Fax Class 3 (Not supported)

+F<command>?

Report Active Configuration

Report Active Configuration. +F<command>? interrogates the

modem to determine the active configuration.
The responses are:
+FAA?

0 if auto answer is disabled; 1 if auto answer is
enabled

+FCLASS

0 if in data mode; 1 if in fax class 1

+FF?

0 if flow control off; 1 if flow control on

+F<command>=?

Report Operating
Capabilities

Report Operating Capabilities. +F<commands>=? can be used to
determine the operating capabilities of the modem.
The responses are:
+FAA=?

0, 1

+FCLASS=? 0, 1
+FTM=?

24, 48, 72, 96

+FTM=?

24, 48

+FTH=?

+FF=?

0,1

+FAA=n

Data/Fax Auto Answer

n = 0

Data/Fax Auto Answer. +FAA command configures the modem to
automatically detect whether an incoming call is from a data
modem or a fax modem. This command is valid in both data and
fax modes.
n = 0 Disable data/fax auto answer mode (default).
n = 1 Enable data/fax auto answer mode. The modem

determines calling type and issues DATA result code (13) if
caller is a data modem, or issues FAX result code (15) in
the caller is a fax modem.

+FF

Enhanced Flow Control

n = 0

Enhanced Flow Control. +FF=n command enables an enhanced
flow control mode for data transfer between the DTE and DCE.
n = 0

Disables enhanced flow control interface. In this mode,
data transfer is compatible with the EIA-578 standard.

n = 1 Enables enhanced flow control.

+FTS=n

Stop Transmission and Wait

n = 0

Stop Transmission and Wait. +FTS=n causes the modem to
terminate a transmission. After temination the modem waits for n
10ms intervals before responding with the OK result code. An
ERROR response code results if this command is issued while the
modem is on-hook.

+FRS=n

Receive Silence

n = 0

Receive Silence. +FRS=n causes the modem to report back to the
DTE with an OK result code after n 10-millisecond intervals of
silence have been detected on the line. This command is aborted if
any command character is received. The modem discards the
aborting character and issues an OK result code. An ERROR
response code results if this command is issued while the modem
is on-hook.

4.0 AT Commands

RC224ATL/224ATLV

EmbeddedModem Family

4-8

Conexant

D224ATLVDSC

+FTM=n

Transmit Data

n = 48

Transmit Data. +FTM=n causes the modem to transmit data using
the modulation defined below. An ERROR response code results if
this command is issued while the modem is on-hook.
+FTM=24

V.27 ter 2400 bps

+FTM=48

V.27 ter 4800 bps

+FTM=72

V.29 7200 bps

+FTM=96

V.29 9600 bps

+FRM=n

Receive Data

n = 48

Receive Data. +FRM=n causes the modem to enter the receiver
mode using the modulation defined below. An ERROR response
code results if this command is issued while the modem is
on-hook.
+FRM=24

V.27 ter 2400 bps

+FRM=48

V.27 ter 4800 bps

+FRM=72

V.29 7200 bps (Not supported

(1)

)

+FRM=96

V.29 9600 bps (Not supported

(1)

)

+FTH=n

Transmit Data with HDLC
Framing

n = 3

Transmit Data with HDLC Framing. +FTH=n causes the modem to
transmit data framed in HDLC protocol using the modulation
defined below. An ERROR response code results if this command
is issued while the modem is on-hook.
+FTH=3

V.21 Channel 2300 bps

+FRH=n

Receive Data with HDLC
Framing

n = 0

Receive Data with HDLC Framing. +FRH=n causes the modem to
receive frames in HDLC protocol using the modulation defined
below. An ERROR response code results if the command is issued
while the modem is on-hook.
+FRH=3

V.21 Channel 2300 bps

+FRTn

Receive Test Data

n = 48

Receive Test Data. +FRTn causes the modem to go off-hook and
begin demodulating received data at the specified rate.

Configuration/Data Rate

n = 24

V.27 ter 2400 bps

n = 48

V.27 ter 4800 bps

+FTTn = m

Transmit Test Data

n = 96

m = 0

Transmit Test Data. +FTTn = m causes the modem to transmit a
continuous test pattern at the specified rate. The transmission will
terminate by a DTE abort (i.e., any character recognized at the DTE
interface).

Configuration/Data Rate

n = 24

V.27 ter 2400 bps

n = 48

V.27 ter 4800 bps

n = 72

V.29 7200 bps

n = 96

V.29 9600 bps

Test Pattern

m = 0

ASCII data (20h - 7Fh sequential)

m = 1

All zeros

m = 2

All ones

m = 3

Alternate 10

m = 4

Sliding 0 (01111)

m = 5

Sliding 1 (00001)

NOTE(S):

(1)

Modem will respond with ERROR result code.

Table 4-3. Fax Command Set Summary (2 of 2)

Fax Command

Function

Default

Parameters/Description

D224ATLVDSC

Conexant

5-1

5.0 S Registers

The S register commands are summarized in

Table 5-1

. The range of possible

values and the factory default value for each S register are also shown. The
factory default values are used whenever the &F command is received or a parity
error is detected in the NVRAM upon modem power turn-on.

The user-defined S registered default values are used at modem power turn-on

or when a modem reset is received. If the NVRAM is not available or contains a
parity error, the factory default S register values are used.

The S registers are described in

Table 5-2

Reading an S Register

The command Sn? reads the current value of an S register, where "n" is the
decimal number of the register.

Example: To read the current value in register S0 (Ring to Answer On) and S7

(Wait Time for Data Carrier), perform the following:

Enter: AT S0? S7? (Value in register S0? Value in register S7?)
A typical response to the might be:
Result: 001 (modem will answer on first ring)
Result: 030 (modem will wait 30 seconds for a carrier)
Result: OK (command completed)

5.0 S Registers

RC224ATL/224ATLV

EmbeddedModem Family

5-2

Conexant

D224ATLVDSC

Table 5-1. S Register Summary

Register

Range

Units

Default

Description

(1)

0255

Rings

Rings to Auto-Answer

0255

Rings

Ring Counter

0127

ASCII

Escape Character

0127

ASCII

Carriage Return Character

0127

ASCII

Line Feed Character

032, 127

ASCII

Backspace Character

2255

Seconds

Maximum time to Wait for Dial Tone

1255

Seconds

Wait for Carrier

0255

Seconds

Pause Time for Comma

1255

1/10 seconds

Carrier Detect Response Time

S10

1255

1/10 seconds

Carrier Loss Disconnect Time

S11

50255

DTMF Dialing Speed

S12

0255

1/50 seconds

Escape Prompt Delay

S14

(1)

Bit Mapped

None

AA hex

General Bit Mapped Options

S16

Bit Mapped

None

Test Mode Bit Mapped Options (&T)

S17

0250

4 ms increments

Fax Mode Null Byte Timer

S18

(1)

0255

Seconds

Test Timer

S19

None

Conexant Protocol Interface Speed

S20

0127

Seconds

Fax Mode Inactivity Timer

S21

(1)

Bit Mapped

None

General Bit Mapped Options

S22

(1)

Bit Mapped

None

76 hex

General Bit Mapped Options

S23

(1)

Bit Mapped

None

General Bit Mapped Options

S24

0255

Seconds

Sleep Inactivity Timer

S25

(1)

0255

0.1 or 1 seconds

Delay to DTR Off

S26

(1)

0255

0.01 seconds

RTS-to-CTS Delay

S27

(1)

Bit Mapped

None

40 hex

General Bit Mapped Options

S28

(1)

Bit Mapped

None

General Bit-Mapped Options

NOTE(S):

(1)

RC224ATL/224ATLV

5.0 S Registers

EmbeddedModem Family

D224ATLVDSC

Conexant

5-3

Table 5-2. S Register Description (1 of 8)

Register

Default

Range

Units

Description

0255

Rings

Ring to Answer On. Assigning S0 a value from 1 to 255 places the
modem in auto-answer mode. The modem will auto answer after
the specified number of rings has occurred.

Setting S0 to 0 disables auto-answer.

0255

Rings

Ring Count. S1 is incremented each time a ring is detected. It will
be cleared if no ring occurs within 8 seconds after the last ring.

0127

ASCII

Escape Code Character. S2 holds the ASCII value used for the
escape code. The + character responds to the factory default value.
Values greater than 127 disable the escape code operation. To
enter the command mode when the escape code is disabled, a loss
of carrier must occur or DTR must be set to a 0 (dependent on &D
command).

127

ASCII

Carriage Return Character. S3 holds the ASCII value for the
carriage return; 13 is the standard value. The character in S3 is
both the command line terminator and the result code terminator.

127

ASCII

Line Feed Character. S4 holds the ASCII value for the line feed.
The line feed character is output after the carriage return only
when English word result codes have been selected (V1). If a line
feed character is not desired, it may be changed to a null, but it
cannot be totally disabled.

32, 127

ASCII

Backspace Character. S5 holds the ASCII value for the backspace
character. This character is both the backspace key and the
character echoed to move the cursor back one position. Normally
a value of 8 is used. The backspace character must not be set to a
value corresponding to a printable ASCII character (i.e., between
33 and 126) or to a value greater than 127. A backspace is used as
follows:

The keystroke is echoed back to the terminal and the cursor moved

back over the last character entered. The last character in the com-
mand buffer is deleted.

255

Seconds

Wait for Dial Tone. S6 specifies the wait time before dialing. The
delay allows time for the dial tone to occur on the telephone line.
The minimum time is 2 seconds. Values greater than 2 seconds
may be necessary if trouble is encountered getting dial tones.

255

Seconds

Wait for Carrier After Dial. S7 specifies the delay time that the
modem waits for the carrier signal from the remote modem before
hanging up. Typically, a delay time of 30 seconds is enough, but it
can be extended to 255 seconds. If the carrier is not detected
within the specified time period, the modem hangs up and sends
the NO CARRIER result code. If carrier is detected, the modem
returns the CONNECT result code and goes on-line.

5.0 S Registers

RC224ATL/224ATLV

EmbeddedModem Family

5-4

Conexant

D224ATLVDSC

255

Seconds

Pause Time for the Comma Dial Modifiers. S8 sets the pause
time for the comma dial modifier. The comma is used during
dialing when it is necessary to dial through a PBX and wait for a
second dial tone. A 2-second delay is usually enough. S8 can be
changed or multiple commas can be used to lengthen the delay.

255

1/10

seconds

Carrier Detect Response Time. S9 sets the carrier detect
response time.

S10

255

1/10

seconds

Lost Carrier to Hang Up Delay. S10 sets the delay time between
loss of carrier and hang-up. The modem will not hang-up due to
loss of carrier if the value of S10 is 255.

S11

255

DTMF Dialing Speed. S11 sets the duration and inter-digit delay
of the touch-tones.

S12

255

1/50

seconds

Escape Code Guard Time. S12 sets the escape code guard time.

S13

Reserved

S14

AAh

Bit Mapped

None

General Bit Mapped Options. S14 is the modem option register
with the following bit functions.

Bit 0

Reserved

Bit 1

Command Echo (See E command)

E0No echo

Echo (factory default)

Bit 2

Results Code (See Q command)

Enabled (factory default)

Disabled

Bit 3

Verbose Command (See V command)

Digits

Words (factory default)

Bit 4

Reserved

Bit 5

(1)

Dial Method (See T and P commands)

Tone dial

Pulse dial (factory default)

Bit 6

Reserved

Bit 7

Originate/Answer (See A, D, and R commands, and
register S0)

Answer

Originate (factory default)

S15

Reserved

Table 5-2. S Register Description (2 of 8)

Register

Default

Range

Units

Description

RC224ATL/224ATLV

5.0 S Registers

EmbeddedModem Family

D224ATLVDSC

Conexant

5-5

S16

None

Modem Test Option. Controls the diagnostic modes as follows:

Bit 0

Local Analog Loopback L3 (See &T1 command)

Disabled (factory default)

&T1

Enabled

Bit 1

Reserved

Bit 2

Local Digital Loopback (See &T3 command)

Disabled (factory default)

&T3

Enabled

Bit 3

Remote Digital Loopback L2 (See &T6 command)

Disabled (factory default)

&T6

Enabled

S17

0-250

4 ms

Increments

Fax Mode Null Byte Timer. The value of S17 determines the
length of time null bytes are sent by the modem if the last byte
sent during DTE underrun in Fax Mode is not a null byte.
0

S17

250 corresponds to a timer value of 01 second (i.e.,

the timer value is the value of S17 times 4 ms).

S18

0-255

Seconds

Test Timer. Sets the length of time the modem conducts a test
before returning to the command mode. If this register is zero, the
test will not automatically terminate; the test must be terminated
from the command mode by issuing an AT&T0 or ATH command.

S19

Not Supported

S20

1-127

Seconds

Fax Mode Inactivity Timer. S20 can be used to cause the modem
to automatically place the telephone on-hook or reset itself if
inactivity (of variable duration) is detected while in Fax Mode.

Table 5-2. S Register Description (3 of 8)

Register

Default

Range

Units

Description

5.0 S Registers

RC224ATL/224ATLV

EmbeddedModem Family

5-6

Conexant

D224ATLVDSC

S21

Bit Mapped

Bit Mapped Options. S21 is the modem register with the following
bit functions:

Bit 0

Telco Jack (See &J Command)

&J0

11/RJ-45S (factory default)

&J1

RJ-12/RJ-13

Bit 1

Reserved

Bit 2

Ready to Send (RTS)/Clear to Send (CTS). (See &R
Command)

&R0

CTS tracks RTS (not supported)

&R1

RTS is ignored (factory default)

Bit 3, 4

Data Terminal Ready (DTR) (See &D Command)

4 3

0 0

&D0

Modem ignores DTR (factory default)

0 1

&D1

Modem goes to command state if

ON-to-OFF transition on DTR

1 0

&D2Modem "hangs up" if ON-to-OFF
transition on DTR

1 1

&D3

Modem goes to initialization state if

ON-to-OFF transition on DTR

Bit 5

Data Carrier Detect (DCD) (See &C Command)

&C0

DCD is always on (factory default)

&C1

An ON condition on DCD indicates the

presence of a valid data carrier

Bit 6

Data Set Ready (DSR) (See &S Command)

&S0

DSR is always on

&S1

DSR is turned on at the start of

handshaking

Bit 7

Long Space Disconnect (See Y Command)

&Y0

Disabled (factory default)

&Y1

Enabled

Table 5-2. S Register Description (4 of 8)

Register

Default

Range

Units

Description

RC224ATL/224ATLV

5.0 S Registers

EmbeddedModem Family

D224ATLVDSC

Conexant

5-7

S22

76h

Bit Mapped

Bit Mapped Options. S22 is the modem register with the following
bit functions:

Bit 0, 1

Speaker Volume (See L Command)

1 0

0 0

Speaker volume low

0 1

Speaker volume low

1 0

Speaker volume medium (factory default)

1 1

Speaker volume high

Bit 2, 3

Speaker Control (See M Command)

3 2

0 0

Speaker disabled

0 1

Speaker on until carrier detected (factory

default)

1 0

Speaker always on

1 1

Speaker on until carrier detected but off

during dialing

Bit 4, 5, 6Result Code Options (See X Command)

6 5 4

0 0 0

Selects appropriate connect result code,

goes off-hook when the dial command is
received, waits the number of nds given by
register S6, and "blind dials" (does not look
for dial tone).

0 0 1

Reserved

0 1 0

Reserved

0 1 1

Reserved

1 0 0

Selects appropriate connect result code,

goes off-hook, waits the number of seconds
specified by register S6 and blind dials
without waiting for dial tone. Busy is not
detected.

1 0 1

Selects appropriate connect result code,

goes off-hook, and dials when dial tone is
detected. Busy is not detected.

1 1 0

Selects appropriate connect result code,

goes off-hook, waits the number of seconds
specified in register S6, blind dials, detects
busy signal and sends BUSY result code.

1 1 1

Selects appropriate connect result code,

goes off-hook and dials when dial tone is
detected, detects busy signal and sends BUSY
result code. All result codes are enabled
(factory default).

Bit 7

Make/Break Ratio (See &P Command)

&P0

39/61 United States/Canada (factory

default)

&P1

33/67 UK/Hong Kong

Table 5-2. S Register Description (5 of 8)

Register

Default

Range

Units

Description

5.0 S Registers

RC224ATL/224ATLV

EmbeddedModem Family

5-8

Conexant

D224ATLVDSC

S23

Bit Mapped

Bit Mapped Options.

Bit 0

Obey request from remote modem for a Remote Digital
Loopback (See &T4 and &T5 Commands)

&T5 selected

RDL disabled

&T4 selected

RDL enabled (factory default)

Bit 1, 2

Communications Rate

2 1

0 0

300 bps

0 1

Reserved

1 0

1200 bps

1 1

2400 bps (factory default)

Bit 3

Reserved

Bit 4, 5

Parity Option

5 4

0 0

Even parity (factory default)

0 1

Space parity

1 0

Odd parity

1 1

Mark/None parity

Bit 6, 7

Guard Tones (See &G Command)

7 6

0 0

&G0

Guard tone disabled (factory default)

0 1

Reserved

1 0

&G2

1800 Hz guard tone

1 1

Reserved

S24

0-255

Seconds

Sleep Mode Inactivity Timer. S24 is used to set the amount of
time the modem may be inactive before it will enter sleep mode.
The range of S24 is 0

S24

4, and Sleep Mode is inhibited when

S24 = 255. (Also see Sleep Mode Signals in

Table 3-5

S25

0-255

0.01 or 1

Seconds

Detect DTR Change. If &Q1 is selected, S25 is the delay in
seconds after a connection has been made, but before the modem
examines the DTR lead.

If in the on-line or on-line command state, changes in DTR that last

less than the time specified by S25, in 0.01 sec increments, are
ignored by the modem.

S26

0-255

0.01

Seconds

RTS to CTS Delay Intervals. Reserved

Table 5-2. S Register Description (6 of 8)

Register

Default

Range

Units

Description

RC224ATL/224ATLV

5.0 S Registers

EmbeddedModem Family

D224ATLVDSC

Conexant

5-9

S27

40h

Bit Mapped

Bit Mapped Options.

Bit 3, 1, 0Communications Mode Option (See &D Command)

3 1 0

0 0 0

&Q0 selected

Asynchronous (factory

default)

0 0 1

&Q1 selected

Synchronous (not supported)

0 1 0

&Q2 selected

Synchronous (not supported)

0 1 1

&Q3 selected

Synchronous (not supported)

1 0 0

Reserved

1 0 1

Reserved

1 1 0

Reserved

1 1 1

Reserved

Bit 2

Dial Up/Leased Line Option

Dial Up (factory default)

Leased Line (not supported)

Bit 4, 5

Synchronous Transmit Clock Source Selection (See &X
Command)

5 4

0 0

&X0

Internal Clock (factory default)

0 1

&X1

External DTE Clock (not supported)

1 0

&X2

Receive Clock (not supported)

1 1

Reserved

Bit 6

Communications Standard Option (See B Command)

CCITT V.22 bis/V.22

Bell 212A (factory default)

Bit 7

Data/Fax Discrimination (i.e., AT+FAA Status)

Data/Fax auto answer mode disabled
(AT+FAA = 0)

Data/Fax auto answer mode enabled
(AT+FAA = 1)

Table 5-2. S Register Description (7 of 8)

Register

Default

Range

Units

Description

5.0 S Registers

RC224ATL/224ATLV

EmbeddedModem Family

5-10

Conexant

D224ATLVDSC

S28

Bit Mapped

Bit Mapped Options.

Bit 2, 1, 0Transmit Level Attenuation (See %Ln Command)

2 1 0

Description

0 0 0

0 dB attenuation

0 0 1

2 dB attenuation

0 1 0

4 dB attenuation

0 1 1

6 dB attenuation

1 0 0

8 dB attenuation

1 0 1

10 dB attenuation

1 1 0

12 dB attenuation

1 1 1

14 dB attenuation

Bit 5, 4, 3DTMF Transmit Level Attenuation (See %Dn Command)

5 4 3

Description

0 0 0

0 dB attenuation

0 0 1

2 dB attenuation

0 1 0

4 dB attenuation

0 1 1

6 dB attenuation

1 0 0

8 dB attenuation

1 0 1

10 dB attenuation

1 1 0

12 dB attenuation

1 1 1

14 dB attenuation

Bit 6

Dialing Pulses per Second

10 pps

20 pps

Bit 7

Secondary Defaults (See %J Command)

&F defaults

%J defaults

NOTE(S):

(1)

Bit 5 is set or reset if the dial command string contains a P (pulse dial) or T (tone dial), respectively. If a subsequent dial
command string is used with a P or T, the modem uses the option specified by this bit.

Table 5-2. S Register Description (8 of 8)

Register

Default

Range

Units

Description

D224ATLVDSC

Conexant

6-1

6.0 Operation

Modem operation supports data modem processing, fax modem processing and
common call progress processing.

The AT+FCLASS command allows the operator to select either data or fax

operation.

AT+FCLASS=0 Data mode
AT+FCLASS=1 Fax mode Class 1

6.1 Data Modes

6.1.1 Data Mode Selection

Data mode operation is defined by the AT commands and S register settings
described in Chapter 4 and Chapter 5. Data rate selection is determined by the
speed of the originating and answering modems as listed in

Table 6-1

6.1.2 Data Modem Processing

Data modem processing is explicitly defined in CCITT V.22 bis, CCITT V.22,
Bell 212A, and Bell 103 documentation. All modulation, waveform spectrum,
and data processing functions conform to the appropriate specifications with the
following exceptions:

CTS is ON all the time and does not go OFF during handshake.

DSR is always ON in parallel mode operation.

The rate change request option is not supported for V.22 bis.

V.22 operation supports only Alternative B, mode ii (1200 bps
asynchronous, 10 bit characters)

Table 6-1. Data Rate Selection

Answer Mode

Originate Mode

300

1200

2400

300

1200

300

1200

2400

300

1200

2400

RC224ATL/224ATLV

6.0 Operation

EmbeddedModem Family

6.2 Fax Modes

D224ATLVDSC

Conexant

6-3

6.2 Fax Modes

6.2.1 Fax Mode Selection

Fax modes and rates are determined by the AT+F commands and are defined in

Chapter 4.0, AT Commands

6.2.2 Fax Mode Processing

Fax modem processing is explicitly defined in CCITT V.29, CCITT V.27 ter, and
CCITT V.21 recommendations. All modulation, waveform spectrum, and data
processing functions conform to the appropriate specifications with the following
exceptions:

V.29 receive functions are not supported.

V.29 4800 bps is not supported; V.27 ter 4800 bps is used instead.

V.29 half-duplex continuous carrier mode only is supported.

V.29 channel multiplexer option is not supported.

V.27 ter 75-baud backward channel option is not supported.

V.27 ter short train mode is not supported.

6.2.3 Fax Origination

Automatic origination of fax call is supported by the ATDS command. Upon
completion of the dial function, a calling tone at 1100 Hz (± 38 Hz) with an ON
duration of 0.5 seconds (± 75 ms) and OFF duration of 3 seconds (± 450 ms) is
transmitted.

6.2.4 Fax Answering

Answering of fax calls is identical to answering of data calls, with the exception
that the DCE enters the fax handshaking mode instead of the data handshaking
mode after going off-hook.

6.0 Operation

RC224ATL/224ATLV

6.2 Fax Modes

EmbeddedModem Family

6-4

Conexant

D224ATLVDSC

6.2.5 Fax Data Transmission

Fax data transmission is initiated by the +FTM command. Upon recognition of
the command, the modem initiates the selected modulation mode and issues the
CONNECT result code. The proper training sequence for the selected mode is
transmitted, followed by constant 1 bits, until data is received from the DTE. DTE
data is buffered and processed prior to being transmitted. The transmission is
terminated when the transmit buffer becomes empty and the last transmitted
character was not a NUL character. The modem then turns off the carrier and
issues the OK result code. If the last character was a NUL character (00), the
modem continues to transmit NUL characters until more data is received by the
DTE or until 5 seconds have elapsed. After 5 seconds, the modem turns off the
carrier and issues the ERROR result code.

6.2.6 Fax Data Reception

Fax data reception is initiated by the +FRM command. Upon recognition of the
command, the modem initiates the selected demodulation mode and looks for the
proper carrier. When the selected carrier is detected, the modem issues the
CONNECT result code +FCERROR. If a signal other than the selected carrier is
detected, the modem returns to the command state. Demodulated data is stored in
an output buffer for additional I/O processing and eventual output to the DTE.
Detection of loss of carrier will cause the modem to issue the NO CARRIER
result code and will cause the modem to return to the command state. Any
character other than flow control characters issued while the receiver is outputting
data will cause the receiver to abort and return to the command state.

6.2.7 Fax Control Transmission

Fax control transmission is initiated by the +FTH command or after answering a
call. The modem initiates the selected modulation mode, issues the CONNECT
result code, transmits one second of flags, then transmits data sent by the DTE.
DTE data is buffered and processed prior to transmission.

Processed I/O data is grouped into frames and encoded with a CRC generator.

The generator polynomial is X

+ X

+ 1. The CRC parity or frame check

sequence (FCS) is appended to the end of the frame. The end of the frame is
indicated by an empty I/O buffer. Transmission frames begin and end with a flag
sequence (7Eh). The ending flag may serve as the beginning flag for the next
frame. To prevent data from looking like flags, a 0 is inserted into the data stream
after five consecutive 1s are detected.

RC224ATL/224ATLV

6.0 Operation

EmbeddedModem Family

6.2 Fax Modes

D224ATLVDSC

Conexant

6-5

Each frame is checked to see if the current frame is the last frame of the

transmission. If the final frame bit (5th received bit of the second byte of the
frame) is 1, indicating that the current frame is the final frame, the modem
completes the frame transmission, issues the OK result code, and returns to the
command state. If the final frame bit is a 0, the modem issues the CONNECT
result code and continues to transmit flags until one of the following actions is
taken by the DTE:

If additional data is sent by the DTE, the modem transmits another frame.

If the transmission is terminated by the <DLE> <ETX> string, the modem
turns off the carrier and issues the OK result code.

If no data is sent by the DTE within 5 seconds of receiving the CONNECT
message, the modem turns off the carrier and issues the ERROR result
code.

6.2.8 Fax Control Reception

Fax control reception is initiated by the +FRH command or after dialing. Upon
recognition of the command, the modem initiates the selected demodulation mode
and looks for the proper carrier. When the selected carrier is detected, the modem
issues the CONNECT result code. If a signal other than the selected carrier is
detected, the modem issues an +FCERROR result code and returns to the
command state.

The modem removes the flags, removes transmitter inserted 0 bits (a 0

following five consecutive 1s), performs the CRC error checking, and stores the
data in the internal I/O buffer for further processing and eventual passing to the
DTE.

The modem indicates the end of a frame by issuing the <DLE> <ETX>

characters and an OK result code if the frame was received correctly, or by issuing
an ERROR result code if one or more errors were detected in the frame. The first
frame received is stripped of flags (CONNECT result code indicates that a valid
flag has been received) and output to the DTE. Subsequent frames are buffered
and output to the DTE when additional +FRH commands are received.

Any characters other than flow control that are received while demodulating

data and prior to issuance of the status result code will result in the receive
process being aborted, an OK result code being issued, and the modem returning
to the command state. After the status result code is issued, the modem continues
to demodulate data. Additional +FRH commands specifying the same modulation
rate will result in the issuance of a CONNECT result code, output of the next data
frame, and continuation of normal demodulation. Any other commands will result
in the receive process being aborted, buffered data being discarded, and the
command being implemented.

Detection of loss of carrier will result in the modem issuing the NO

CARRIER result code and returning to the command state.

6.2.9 Fax I/O Processing

The fax I/O interface supports asynchronous serial and parallel interfaces. The
interface rate is 19.2 kbps. Start and stop elements are removed from the
incoming serial data stream and are added to the outgoing serial data (receive).

RC224ATL/224ATLV

6.0 Operation

EmbeddedModem Family

6.3 Fax Enhanced Flow Control

D224ATLVDSC

Conexant

6-7

6.3 Fax Enhanced Flow Control

The fax Class 1 standard provides for bidirectional X-on/X-off flow control.
However, in multitasking "windowing" environments, the DTE communication
package can be suspended long enough to miss a 19,200 bps serial asynchronous
character sent by the DCE (520.83 µs). X-on/X-off flow control will not solve this
problem because the DTE software does not always know when it is going to be
suspended. To solve this problem, a new enhanced flow control mechanism is
provided. This mechanism is enabled/disabled by issuing an AT+FF=1/0
command.

6.3.1 Parallel/Serial Interface Selection

For parallel host interface operation, the enhanced flow control takes advantage of
the fact that the DCE hardware knows if the DTE has read the last character. The
DCE will not send a new character until the DTE reads the previous one. The
modem fax receiver has an internal 223-byte buffer. Therefore, the DTE can stop
reading characters for 371 ms (4800 bps receive) before any data is lost.

For serial interface operation, the enhanced flow control mechanism utilizes

the fact that the Fax Class 1 serial interface is only required to operate half
duplex. The scheme involves sending characters to the DTE and waiting for the
DTE to send an acknowledgment (if the DTE reads the character OK) or a request
for re-transmission (if the DTE misses a character and detects an overrun). The
required DTE operation using the enhanced flow control mechanism is defined
below.

6.3.2 Fax V.42 Buffer Sizes

Fax V.42 buffer sizes are shown below.

Buffer Type

Size in Bytes

Fax V.27/V.29 Tx

255 (9600:212 ms)

Fax V.21 (HDLC) Tx

255 (300:6.8 sec)

RPI (HDLC) Tx

238 (2400:793 ms)

Fax V.27 Rx

223 (4800:371 ms)

Fax V.21 (HDLC) Rx

255 (300:6.8 sec)

6.0 Operation

RC224ATL/224ATLV

6.4 Data/Fax Auto Answering

EmbeddedModem Family

6-8

Conexant

D224ATLVDSC

6.3.3 DTE Flow Control Operation

Normal operation:

DTE does not miss character. The DTE reads the serial character sent by the
DCE. The DTE checks serial hardware overrun status and determines that an
overrun did not occur. The DTE can therefore use the character. The DTE must
send the following acknowledgment character back to the DTE.

11111110 (FEh)

Overrun Operation:

DTE misses character. The DTE returns after being suspended and reads the
serial character sent by the DCE. The DTE checks serial hardware overrun status
and determines that an overrun occurred. The DTE does not use the received
character. The DTE then sends the following re-transmission request character
back to the DCE.

11110000 (F0h)

6.4 Data/Fax Auto Answering

Data/fax auto answering, when used with appropriate DTE host software, will
automatically recognize whether an incoming call is a data or fax modem. This
mechanism can be used with an integrated data/fax communication package or
with separate data/fax communication packages operating together in a
foreground/background configuration.

The auto answering mechanism is structured such that the DTE is initially

operating in the fax mode. The DTE enables auto answering using the
AT+FAA=1 command (saved in NVRAM under S27). This command should be
issued while AT+FCLASS=1. The DTE will then change its communication rate
from 19,200 bps (fax class 1 rate) to the rate expected in data mode (2400, 1200,
or 300 bps).

The DCE will attempt to establish a connection with the incoming call as a

data modem. If the incoming call is a fax, the DCE will switch to the fax mode
and establish the connection. To minimize incompatibilities with various fax and
data modems, the 59 register is used to define the length of time that the DCE has
to establish a data connection.

S9 (Range: 0255; Default: 06) defines the time (in seconds) after going off-hook
that the DCE waits for the entire data mode handshaking process to complete
before switching to fax mode.

When a call is received (DCE sends RING result code), the DTE can initiate

the answer manually by sending an ATA command. Alternatively, the DTE can
allow the DCE to answer automatically by setting S0=non-zero value. After the
DCE goes off-hook, it will automatically determine the caller type (data or fax),

RC224ATL/224ATLV

6.0 Operation

EmbeddedModem Family

6.4 Data/Fax Auto Answering

D224ATLVDSC

Conexant

6-9

establish the appropriate connection, and inform the DTE of the caller type with
the following result codes:

It is assumed initially for auto answer operation that the DTE is running the

fax communication package.

It is impractical to force the fax package to use the same options selected by

the data package. Therefore, some method must be provided to allow the DTE fax
package to restore the DCEs registers after the DCE has connected as a data
modem. The DCE accommodates this by automatically entering the on-line
command mode after connecting. After the DTE receives the DATA result code, it
can then send any necessary AT commands to the DCE. The DCE will wait in the
on-line command mode and delay sending the "data" connect message until the
DTE sends an ATO command. After sending the ATO command, the DTE then
transfers control to the data communication package.

For DTEs running separate data and fax packages in a foreground/background

configuration, a method is provided to allow the fax package to regain control
after the data connection has terminated during auto answer mode without
requiring changes to existing data packages. The RC224ATLV accommodates
this through the use of the data carrier detect (DCD) indicator. Initially, in auto
answer mode DCD will be off. When connected in data mode, the DCE will turn
DCD on. When the data connection is terminated, the DCE will turn DCD off
again. The fax package, running in the background, can poll DCD (160450
modem status register bit 7) to ascertain the data connection status. The DTE
must send AT&C1 to cause DCD to operate in this manner.

During auto answer mode, when the caller is a fax machine, the DCE will

behave as a normal fax DCE (as defined by +FCLASS=1) with the following
exceptions:

The transmission of the fax 2100 Hz answer tone will be delayed by the
time needed to determine that the caller is a fax machine (S9 seconds).

The DCE sends FAX message at the data mode DTE rate (as defined by
the previous AT command autobaud rate) and automatically sets
+FCLASS=1 after detecting that the caller is a fax.

After the answer tone is sent and the DCE enters the V.21 transmit mode,
the CONNECT result code will be sent at 19,200.

During auto answer mode, if the DCE determines that the caller is not a data

modem nor a fax machine, then DCE will send the NO CARRIER result code, go
on-hook and remain in data mode.

Table 6-2

describes a procedure to configure a terminal being called by a 1200

bps data modem.

Table 6-3

describes a procedure to configure a terminal being

called by a fax machine with or without calling tone.

Numeric Verbose

Description

13 (0Dh)

DATA

DCE sends this result code only during auto answering or
when DCE has connected as a data modem.

15 (0Fh)

FAX

DCE sends this result code only during auto answer
mode when DCE has connected as a fax modem.

6.0 Operation

RC224ATL/224ATLV

6.4 Data/Fax Auto Answering

EmbeddedModem Family

6-10

Conexant

D224ATLVDSC

Table 6-2. Terminal Called by a 1200 bps Data Modem

DTE Command

DCE Response

Comments

Assume DCE in fax mode (FCLASS = 1), DTE running fax
communication package, and DCD is off.

AT&C1

DTE commands DCD to follow data carrier.

ATS9=n

DTE defines the data mode connection time.

AT+FAA=1

DTE enables data/fax auto answer mode.

DTE sets the communication rate to the data modem rate (e.g., 2400
bps) prior to an incoming call.

RING

Terminal is being called.

ATA

DTE commands DCE to go off-hook and start auto answer.

DCE determines caller as data modem and establishes connection
with caller.

DCE turns on DCD to indicate data connection is established.

DCE then waits in on-line command mode.

DATA

DCE indicates data modem connection is established.

AT commands

DTE optionally sends any commands to DCE to restore conditions
required by data modem communications package.

ATO

CONNECT 1200

DTE instructs DCE to switch from on-line command to data state.

DTE then transfers control to data modem package.

Fax package remains in background polling DCD to check connection
status.

DCE response will then be read by data modem communication rate
to 1200 bps.

"Callers data"

DTE sends/receives data.

Caller hangs up. DTE detects carrier loss and turns off DCD.

NO CARRIER

DCE indicates connection with caller has terminated.

DTE fax communications software, running in background, sees DCD
turn off, and regains control from data modem package.

RC224ATL/224ATLV

6.0 Operation

EmbeddedModem Family

6.4 Data/Fax Auto Answering

D224ATLVDSC

Conexant

6-11

Table 6-3. Terminal Called by a Fax Machine

DTE Command

DCE Response

Comments

Assume DCE in fax mode (FCLASS = 1), DTE is running fax
communication package, and DCD is off.

AT&C1

DTE commands DCD to follow data carrier.

ATS9=n

DTE defines the data mode connection time.

AT+FAA=1

DTE enables data/fax auto answer mode.

DTE sets the communication rate to the data modem rate (e.g., 2400
bps) prior to an incoming call.

RING

Terminal is being called.

ATA

DTE commands DCE to go off-hook and start auto answer.

DCE starts data modem handshaking. If receive data signal is not
detected within S9 seconds from going off-hook, DCE switches to fax
mode and automatically sets FCLASS=1.

FAX

DCE switches to fax mode handshaking and sends "FAX" message at
the data modem rate (e.g., 2400 bps).

DCE sends 3 seconds of 2100 Hz answer tone, enters V.21 transmit
mode, and sends HDLC flags.

CONNECT

DCE ends CONNECT response at the fax rate (i.e., 19,200 bps).

6.0 Operation

RC224ATL/224ATLV

6.5 Call Progress

EmbeddedModem Family

6-12

Conexant

D224ATLVDSC

6.5 Call Progress

6.5.1 Call Progress Algorithms

Data call progress algorithms measure the power and/or relative power of the
highband and lowband channels and determine signal presence and cadence
correlations. Highband channel signals include 2100 and 2225 Hz signalling
tones. Lowband channel signals include dial tones, busy tones, ringback tones and
voice ranging in frequency from 120 to 620 Hz.

Characteristics of the tones detected by the RC224ATLV are listed in

Table 6-4

Fax answer tone detection requirements include 2100 and 1100 Hz. The call

progress detection requirements are identical to the lowband data signals
identified above.

Table 6-4. Tone Characteristics

Tone

Cadence

Frequency (Hz)

Dial Tone

Continuous

350 + 440

Old Dial Tone

Continuous

600+120/133

Busy

0.5 sec ON
0.5 sec OFF

480 + 620
480 + 620

Old Busy

0.5 sec ON
0.5 sec OFF

600 + 120
600 + 120

Precision Reorder

0.3 sec ON
0.2 sec OFF

480 + 620
480 + 620

Old Reorder (local)

0.25 sec ON
0.25 sec OFF

600 + 120
600 + 120

Old Reorder (toll)

0.2 sec ON
0.3 sec OFF

600 + 120
600 + 120

Ringback

0.8-1.2 sec ON
2.7-3.3 OFF

440 + 480
440 + 480

Old Ringback

2 sec ON
4 sec OFF

420 + 40
420 + 40

Double Ringback

0.8 sec ON
0.3 sec OFF
0.8 sec ON
4 sec OFF

440 + 480
440 + 480
440 + 480
440 + 480

RC224ATL/224ATLV

6.0 Operation

EmbeddedModem Family

6.5 Call Progress

D224ATLVDSC

Conexant

6-13

6.5.2 Ring Detection

Ring detection is based on a digital input to the modem. External circuitry not
part of the modem is required to convert the analog 40 to 150 V

RMS

ring signal to

a digital single-bit data stream representation. Valid ring frequencies of 15.3 to 68
Hz are detected. Detection is achieved by counting valid high to low ring signal
transitions. Valid transitions consist of a high state of 2 to 34 ms followed by a low
state of 2 to 42 ms. Ring signals that have transition counts less than the nominal
value are discarded.

In addition to valid high to low transitions, ring detection depends on the

cadence of the ring ON time (valid transitions occurring) and ring OFF time (no
valid transitions). Ring OFF times must be greater than 0.5 seconds. Ring ON
times must be greater than 125 ms at 20 Hz (100 ms at 68 Hz).

Ring detection is integrated over 8 seconds. All counters and timers are reset

at 8 second intervals. The modem will answer the ring after N valid ON/OFF ring
cycles. N is programmable via the S0 register. Upon detecting N rings, the
modem verifies that the current ring state has been in the OFF state for 0.5
seconds before seizing the line.

Table 6-5

lists the Fax Class 1 calling sequence;

Table 6-6

lists the answering

sequence.

Table 6-5. Fax Class 1 Calling Sequence (1 of 2)

DTE Commands

(Host)

DCE Responses

(Modem)

Remote Fax

Notes

(1) AT+FCLASS=1

(2) OK

Set to Class 1

PHASE A

(3) ATDT6163

(4) Dials
(6) CONNECT

(5) Answers
(7) Send HDLC flags

+FRH=3 implied by Dialing

PHASE B

(8) Send NSF frame

(9) <NSF>, OK

(10) AT+FRH=3

(11) CONNECT

(12) Send CSI frame

(13) <CIS>, OK

(14) AT+FRH=3

(15) CONNECT

(16) Send DIS frame

Last frame bit = 1

(17) <DIS>, OK

(18) Drop carrier

(19) AT+FTH=3

(20) Send HDLC flags

(21) Receive flags

(21) CONNECT

(22) <TSI>

(23) Send TSI frame

(24) Receive TSI

Last frame bit = 0

(25) CONNECT

(26) <DCS>

(27) Send DCS frame

(28) Received DCS

Last frame bit = 1

(29) Detect last frame bit

6.0 Operation

RC224ATL/224ATLV

6.5 Call Progress

EmbeddedModem Family

6-14

Conexant

D224ATLVDSC

(30) OK, drop carrier

(31) AT+FTS=8

(32) OK, wait 80 ms

(33) AT+FTM=96

(34) Send F.29

(35) CONNECT

(36) <TCF>

(37) Send TCF data

(38) Receive and check

(39) OK

(40) AT+FRH=3

(41) CONNECT

(42) Send CFR frame

Last frame bit = 1

(43) <CFR>, OK

(44) Drop carrier

(45) OK

PHASE C

(46) AT+FRM=06

(47) Send V.29

(48) CONNECT

(49) Page data

(50) Send page data

(51) Receive data

(52) OK

(53) AT+FTH=3

(54) Send HDLC flags

(55) Receive flags

(56) CONNECT

PHASE D

(57) <EOP>

(58) Send EOP frame

(59) Receive EOP

Last frame bit = 1

(60) OK, drop carrier

(61) AT+FRH=3

(62) CONNECT

(63) Send MCF frame

Last frame bit = 1

(64) <MCF>,OK

(65) AT+FTH=3

(66) Send HDLC flags

(67) Receive flags

(68) CONNECT

(69) <DCN>

(70) Send DCN frame

(71) Receive DCN

Last frame bit = 1

(72) OK, drop carrier

PHASE E

(73) ATH0

(74) OK, hang up

(75) Hang up

Table 6-5. Fax Class 1 Calling Sequence (2 of 2)

DTE Commands

(Host)

DCE Responses

(Modem)

Remote Fax

Notes

RC224ATL/224ATLV

6.0 Operation

EmbeddedModem Family

6.5 Call Progress

D224ATLVDSC

Conexant

6-15

Table 6-6. Fax Class 1 Answering Sequence (1 of 2)

DTE Commands

(Host)

DCE Responses

(Modem)

Remote Fax

Notes

(1) AT+FCLASS=1

(2) OK

Set to Class 1

(2b) AT+FRM=?

24,48

PHASE A

(3) FAX machine dials

(4) RING

(5) ATA

(6) Modem answers

(7) Send HDLC flags

(8) Receive flags

+FTH=3 implied by answering

(9) CONNECT

PHASE B

(10) <NSF>

(11) Send NSF frame

(12) Receive NSF

Last frame bit = 0

(13) CONNECT

(14) <CSI>

(15) Send CSI frame

(16) Receive CSI

Last frame bit = 0

(17) CONNECT

(18) <DSI>

(19) Send DSI frame

(20) Receive DSI

Last frame bit = 1

(21) OK, drop carrier

(22) AT + FRH=3

(23) CONNECT

(24) Send TSI frame

Last frame bit = 0

(25) <TSI>,OK

(26) AT+FRH=3

(27) CONNECT

(28) Send DCS frame

Last frame bit = 1

(29) <DCS>,OK

(30) Drop carrier

(31) AT+FTH=3

(32) Send V.27 (4800)

(33) CONNECT

(34) Send TCF frame

(35) <TCF>

(36) Drop carrier

(37) NO CARRIER

(38) AT+FRM=48

(39) CONNECT

(40) <CFR>

(41) Send CFR frame

(42) Receive CFR

Last frame bit = 1

(43) OK, drop carrier

7.0 Electrical/Mechanical Specifications

RC224ATL/224ATLV

7.3 Interface Timing and Waveforms

EmbeddedModem Family

7-4

Conexant

D224ATLVDSC

Table 7-3. Current and Power Requirements

Mode

Current (ID)

Power (PD)

Typical

Current @ 25°C

Maximum Current

@ 0°C

Typical

Power @ 25°C

Maximum

Power @ 0°C

Operating

20 mA

22 mA

100 mW

110 mW

Sleep - Idle

5 mA

6 mA

25 mW

30 mW

Sleep - Stop

1 mA

5 mW

NOTE(S):

1. Test conditions: VDD = 5.0 V

for typical values; VDD = 5.25 V

for maximum values.

2. Test conditions: VDD = 3.3 V

for typical values; VDD = 3.6 V

for maximum values.

Table 7-4. Absolute Maximum Ratings

Parameter

Symbol

Limits

Units

Supply Voltage

0.5 to + 7.0

Input Voltage

0.5 to VCC + 0.5

Analog Inputs

0.3 to + 5 VAA + 0.3

Voltage Applied to Outputs in High Z State

0.5 to + 5 VDD + 0.5

DC Input Clamp Current

DC Output Clamp Current

Static Discharge Voltage (@ 25°C)

ESD

3000

Latch-Up Current (@ 25°C)

TRIG

200

Operating Temperature Range

0 to + 70

Storage Temperature Range

STG

40 to + 80

NOTE(S):

Stresses above those listed may cause permanent damage to the device. This is a stress rating only, and functional

operation at these or any other conditions above those listed in the operational section of this specification is not implied.
Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

RC224ATL/224ATLV

7.0 Electrical/Mechanical Specifications

EmbeddedModem Family

7.3 Interface Timing and Waveforms

D224ATLVDSC

Conexant

7-5

Table 7-5

lists digital interface characteristics, and

Table 7-6

lists analog interface

characteristics.

Table 7-5. Digital Interface Characteristics

Parameter

Symbol

Min.

Typ.

Max

Units

Test Conditions

(1)

Input High Voltage

Type IA
Type DIO
Type IH

2.0
2.4
30

--
--
--

Input Low Voltage

Type IA, IC, and DO

0.3

0.8

Input Low Voltage

Type IF

RMS

(2)

Input Leakage Current

IA and IC

µAdc

= 0 to V

Output High Voltage

Type OA
Type OD
Type OG
Type OH

2.4
--
--
5

--
--
--
8

--
V

LOAD

= -100 µA

LOAD

= 0 mA

Output Low Voltage

Type OA
Type OB
Type OD
Type OG
Type OH

--
--
--
0.5
8

--
--
0.75
--
5

0.4
0.4
--
--
--

LOAD

= 1.6 mA

LOAD

= 0.8 mA

LOAD

= 15 mA

LOAD

= 8 mA

Three-State (off) Current

µAdc

= 0.8 V to 4.5 V

NOTE(S):

(1)

RC224ATL Test Conditions: V

= 5 V 5%

= 0°C to 70°C (unless otherwise stated).

RC224ATLV Test Conditions: V

= 3.3 V 5%

= 0°C to 70°C (unless otherwise stated).

Output loads: 50 pF + one TTL.

(2)

AC V

RMS

voltage between Tip and Ring, using the on-board modular DAA.

Appendix A: RC224ATF Modem Designs

RC224ATL/224ATLV

A.1 68-Pin PLCC Design for Serial Interface

EmbeddedModem Family

A-2

Conexant

D224ATLVDSC

Figure A-1. Serial Interface Design

DECOUPLING CA

TO V.24

EIA-232-

INTERFAC

TRANSCEIVE

TO DAA

INTERFACE

OH*

TXA2

TXA1

RXA

DTR*

RI*

CTS*

DSR*

RXD*

CI*

DCD*

TXD*

RING*

VCC

2200

2.2K

C10

C11 .1

C13

16V

LS1

16120

C18

1000 p

C19

C6 22 10V

56 pF

C17

56 pF

.000312MHZ

C14

LM386

HY93C46J

VCC

GND

C16

220

16V

C15

C12

C22 .1

C9 12

10%

20V

C21

R17

4.7K

R6781-11

VCC

NMI*

XTLO

XTLI

AAE*

DCDL*

PH2

TEST*

RESET*

DTRL*

MR*

IDLENO

DTR*

IDLEN1

WAKEUP*

TXD*

RI*

CTS*

RXD*

CI*/HS

DCD*

DSR*

SEREN*

DGND1

DGND2

VAA

TDACO

TDACI

MODEO

MODEI

TRSTO

TRSTI

RRSTO

RRSTI

RSTBO

RSTBI

TSTBO

TSTBI

RADCO

RADCI

RAGCO

RAGCI

TLKRLY*

OHRLY*

RXA

TXA1

TXA2

RING*

A/A1*

AGCIN

RFILO

SLEEP*

SLEEPI*

SPKR

AGND

NVRDIO

NVRSK

NVRCS

R13

R14

R15

R18

R19

D10

R20

D11

R21

D12

R22

D13

R16

330K

R12

100

RC224ATL/224ATLV

Appendix A: RC224ATF Modem Designs

EmbeddedModem Family

A.2 68-Pin PLCC Design for Parallel Interface

D224ATLVDSC

Conexant

A-7

Figure A-3. Parallel Interface Design

DECOUPLING CA

TO DAA

INTERFAC

HCS*

HDIS

OH*

TXA2

RING*

HWT*

HRD*

HA0

HA1

HA2

RESE

HINT

HD0

HD1

HD2

HD3

HD4

HD5

HD6

HD7

TXA1

RXA

VCC

C5 2200

2.2K

C10

C11

C13

16V

L1 47

22 10V

56P

C14

LM386

HY93C46J

VCC

GND

C15

C9 12 10%

20V

C21

R13

10K

781

VCC

NMI*

XTLO

XTLI

IDLENO

TEST*

HINT

HCS*

HDIS

IDLENI

HD0

HD1

HD2

HD3

HD4

HD5

HD6

HD7

HWT*

HRD*

HA0

HA1

HA2

RESET*

DGND1

DGND2

AGND

VAA

TDACO

TDACI

MODEO

MODEI

TRSTO

TRSTI

RRSTO

RRSTI

RSTBO

RSTBI

TSTBO

TSTBI

RADCO

RADCI

RAGCO

RAGCI

TLKRLY*

OHRLY*

RXA

TXA1

TXA2

RING*

A/A1*

AGCIN

RFILO

SLEEP*

SLEEPI*

SPKR

PH2

NVRDIO

NVRSK

NVRCS

C19 .1

R12

100

C16 220

16V

C18 1000 p

C12

.000312MHZ

LS1

16120

Further Information
literature@conexant.com
1-800-854-8099 (North
America)
33-14-906-3980
(International)

Web Site
www.conexant.com

World Headquarters

Conexant Systems, Inc.
4311 Jamboree Road
P. O. Box C
Newport Beach, CA
92658-8902
Phone: (949) 483-4600
Fax: (949) 483-6375

U.S. Florida/South America
Phone: (813) 799-8406
Fax: (813) 799-8306

U.S. Los Angeles
Phone: (805) 376-0559
Fax: (805) 376-8180

U.S. Mid-Atlantic
Phone: (215) 244-6784
Fax: (215) 244-9292

U.S. North Central
Phone: (630) 773-3454
Fax: (630) 773-3907

U.S. Northeast
Phone: (978) 692-7660
Fax: (978) 692-8185

U.S. Northwest/Pacific West
Phone: (408) 249-9696
Fax: (408) 249-7113

U.S. South Central
Phone: (972) 733-0723
Fax: (972) 407-0639

U.S. Southeast
Phone: (770) 246-8283
Fax: (770) 246-0018

U.S. Southwest
Phone: (949) 483-9119
Fax: (949) 483-9090

APAC Headquarters

Conexant Systems
Singapore,

Pte. Ltd.

1 Kim Seng Promenade
Great World City
#09-01 East Tower
Singapore 237994
Phone: (65) 737 7355
Fax: (65) 737 9077

Australia
Phone: (61 2) 9869 4088
Fax: (61 2) 9869 4077

China
Phone: (86 2) 6361 2515
Fax: (86 2) 6361 2516

Hong Kong
Phone: (852) 2827 0181
Fax: (852) 2827 6488

India
Phone: (91 11) 692 4780
Fax: (91 11) 692 4712

Korea
Phone: (82 2) 565 2880
Fax: (82 2) 565 1440

Europe Headquarters

Conexant Systems France
Les Taissounieres B1
1681 Route des Dolines
BP 283
06905 Sophia Antipolis
Cedex
France
Phone: (33 4) 93 00 33 35
Fax: (33 4) 93 00 33 03

Europe Central
Phone: (49 89) 829 1320
Fax: (49 89) 834 2734

Europe Mediterranean
Phone: (39 02) 9317 9911
Fax: (39 02) 9317 9913

Europe North
Phone: (44 1344) 486 444
Fax: (44 1344) 486 555

Europe South
Phone: (33 1) 41 44 36 50
Fax: (33 1) 41 44 36 90

Middle East Headquarters

Conexant Systems
Commercial (Israel) Ltd.
P. O. Box 12660
Herzlia 46733, Israel
Phone: (972 9) 952 4064
Fax: (972 9) 951 3924

Japan Headquarters

Conexant Systems Japan
Co., Ltd.
Shimomoto Building
1-46-3 Hatsudai,
Shibuya-ku, Tokyo
151-0061 Japan
Phone: (81 3) 5371-1567
Fax: (81 3) 5371-1501

Taiwan Headquarters

Conexant Systems, Taiwan
Co., Ltd.
Room 2808, 333
International Trade Building
Keelung Road, Section 1
Taipei 110, Taiwan, ROC
Phone: (886 2) 2720 0282
Fax: (886 2) 2757 6760

cross ref

0.0 Sales Offices

Document Outline

Ð­Ð»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: RC224ATLV

Document Outline

ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: RC224ATLV