1
* This specification are subject to be changed without notice.
4.28.1999
EM91850
TONE/PULSE DIALER WITH HF, HD, REDIAL
AND VOLUME CONTROL FUNCTION
Preliminary
GENERAL DESCRIPTION
The EM91850 are tone/pulse switchable dialer with Last Number Redail (LNB) and SAVE function, which are
fabricate in CMOS technology with wide operating voltage for both tone and pulse mode. EM91850 consumes very
low memory retention current in on hook state. The EM91850 provide necessary functions of telephone set for
application in any environment, such as pulse dialing, tone (DTMF) dialing, handfree dialing. Beside this, hold , mute
and redial function are provide for particular operation. In redial mode EM91850 can auto insert pause
time for
application in PABX system. EM91850 also have a special I/O pin - VAO can used to
control the receive volume
amplify circuit.
FEATURES
Volume add Control Function.
One key Redial Function.
Flash key is available and have multiple Flash time ( 600 ms, 300 ms, 100 ms ) can be selected.
Auto Insert Pause Time.
Tone/Pulse Switchable.
Pulse mode fixed 10PPS.
Pulse to tone ( P
T ) key is provided for PABX operation.
Many options can be selected by R option.
Mode ( Pulse, Tone )
M/B ratio ( 40:60 ; 33:66 )
Auto insert pause time ( enable ; disable )
One set 32 digits SAVE function.
One set 32 digits LNB redial function.
Mixed and cascaded dialing.
Hold and Mute function.
Hand Free dialing.
Tone duration and inter -tone pause are fixed at 90 ms.
Flash pause time are fixed at 600 ms.
Pulse to Tone pause time are fixed at 3.6sec.
Uses 3.579545 MHz crystal or ceramic resonator (with built-in capacitor, no need extra capacitor).
Package in DIP 16.
Total System
Operating voltage : 2.0V ~ 5.5V
Operating current : Tone mode 0.3 mA (typical) ~ 0.5 mA
Pulse mode 0.15 mA (typical) ~ 0.2 mA
Standby current : 0.01 uA ( typical ) 0.1 uA (max.)
Use single clock 3.579545 MHz crystal
* This specification are subject to be changed without notice.
2
4.28.1999
EM91850
TONE/PULSE DIALER WITH HF, HD, REDIAL
AND VOLUME CONTROL FUNCTION
Preliminary
PIN DESCRIPTIONS
Symbol
Function
K2 , K3 , K5
Key board scan I/O pins, key scans by ripple way.
I/O pin
These pins output 16K Hz signal one by one and periodically for key board scan.
K1/HDO
This pin has two functions.
Normally this pin will be a Key board scan pins function same as K1~K6.
In Hold condition this pin will stay in "High" level to control the Hold circuit and scan HD
input key. In Hold condition all key will not allow keying except HD, HF and Hook switch.
K4/MuteO
This pin has two functions
Normally this pin will be a Key board scan pins function same as K1~K6.
In MUTE condition this pin will stay in "High" level and output signal with the inverse of key
scan to control the MUTE circuit and scan input key . Any key input will release MUTE
condition.
K6/XMUTE
This pin has two functions
Normally this pin will be a Key board scan pins function same as K1~K6.
The Tone/Pulse dialing Mute signal output pin. This pin will switch to "High" level during
Tone/Pulse dialing and hold function. Otherwise, this pin DC level stays "Low".
VDD, VSS
Positive and negative power supply input pin
Xin , Xout
Oscillator input and output pins , built in two 5pf capacitor so it's not need external capacitor.
A 3.579545 MHz crystal must be crossed between Xin and Xout.
HFI
Handfree function Input pin accepts rising edge signal to turn "on" or turn "off" handfree
function. This pin is hysteresis input structure and built-in pull down resistor (typically 200
K
).
HFO
Handfree outputs pin that is designed to control telephone line for on-hook dialing or control
speakerphone circuit for handfree conversation. When handfree function is executed, this pin
will switch to "High". Otherwise, this pin stays "Low" level.
HKS
Hook Switch detects input pin , which is hysteresis input structure and without internal pull
up resistor.
DTMF
DTMF (Dual Tone Multi-Frequency) output pin, In tone dialing mode, this pin will output
DTMF signal that is corresponding to key board 0~9, *, # key.
PO
Pulse signal output pin that is NMOS open-drain. This pin is for pulse dialing. This output is
"Low" during pulse dialing blank duration and Flash operation active, otherwise will be "High
impedance".
VAO
Volume Add output pin , which is open drain structure.
Normally this pin will stay in "High Impedance". When Volume add active and dialer in OFF-
HOOK mode operting then this pin will output "Low".
PIN ASSIGNMENTS
EM91850
K6/XMUTE
K5
K4/MUTEO
XIN
XOUT
VSS
VAO
HFI
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
K3
K2
K1/HDO
DTMF
PO
HKS
VDD
HFO
3
* This specification are subject to be changed without notice.
4.28.1999
EM91850
TONE/PULSE DIALER WITH HF, HD, REDIAL
AND VOLUME CONTROL FUNCTION
Preliminary
KEYBOARD DESCRIPTION :
Key
Description
0~9,*,#
Digit key.
F1 , F2 , F3
Flash key, flash time F1=600ms F2=300ms F3=100ms.
*/T
In Pulse mode, this key mean Pulse to Tone function key.
RD
Redial and One key Redial key.
P
Pause key.
HD
Hold function key, at hold mode to key in "HD" key will go to idle On-hook
state.
HF
Handfree function key.
SAVE
SAVE function key.
VA
Volume Add key.
MUTE
MUTE key. When this key be pressed MuteO output will be "high", and
any key-in will release mute.
Key Assignment :
HD
SAVE
1
2
3
4
5
6
7
8
9
*/T
0
#
MUTE
RD
VA
F1
F2
F3
P
K1
K2
K3
K4
K5
K6
HDO
MuteO
R_option
R_option
XMUTE
R
R
R
* This specification are subject to be changed without notice.
4
4.28.1999
EM91850
TONE/PULSE DIALER WITH HF, HD, REDIAL
AND VOLUME CONTROL FUNCTION
Preliminary
FUNCTION DESCRIPTIONS
Dialer Option selection
The EM91850 incorporated a special keyboard scanning function that is connecting a resistor ( typically is
560 K
) on keyboard scan pin to select many telephone specifications.
The specifications are described as follow :
a. M/B ratio
K2
M/B ratio
NR
40:60
R-Vss
33:66
b. Auto Insert Pause time
d. Mode
K3
Auto Insert
K5
Mode
Pause time
NR
Disable
NR
Tone
R-Vss
Enable
R-Vss
Pulse
Normal Dialing :
Press the digital key directly on keyboard which number can be dialing out and stored in LNB memory auto
matically. Operating procedure described as following:
To select Pulse or Tone mode.
Off-Hook or turn on HF function.
Keying d1,d2,....dn. The "d" expressed digital key pressed that include 1~9, *, 0, #, P, and P
T keys. The "n"
expressed unlimited.
The numbers d1,d2,......, dn will be dialed out in Pulse or Tone mode as selection.
LNB Redial Function :
Storing :
In normal dialing mode, every digital key was entry which number will be stored in LNB memory automatically.
If entry digits are more than 32 digits, the redial function of LNB memory will be disabled, otherwise, these
numbers stored in LNB memory can be redial output.
Redialing :
EM91850 provide Redial and One Key Redial function
(1) Redial function
Off-Hook normal dialing directly keying "F" key (or ON-OFF Hook once) and key-in "RD" keyboard.
The numbers stored in LNB memory will be dialed out.
(2) One Key Redial function
Off-Hook normal dialing, if busy, press the "RD" key directly then the line will be broken about 1.2 sec
with Trp redial pause time and dial out the numbers stored in LNB memory automatically.
5
* This specification are subject to be changed without notice.
4.28.1999
EM91850
TONE/PULSE DIALER WITH HF, HD, REDIAL
AND VOLUME CONTROL FUNCTION
Preliminary
Auto Insert Pause Time Function
EM91850 Provides a new function - Auto Insert Pause Time function - for PABX system user. In PABX
system, we usually use a special number to identify the phone want dial out or just a internal phone. So between
the first and second number, the PABX system will switch to central office, that will be few second switch time.
The auto insert pause time function will auto insert the pause time between first and second digit in redialing mode.
This function are provide a pause time to wait PABX switch to Central Office. In fact, the pause time are record
the waiting time of last dialing between the first and second digit. The auto insert pause minimum duration are equal
0 second, maximun duration are equal 3.5 second, and pause duration scale are 0.1 second. So, if the time during
user keying first and second digit are longer than 3.5 second, the auto insert pause time will be limited at 3.5 second.
By this function, we can redial the correct number out in PABX system.This function can select enable or disable
by R_option.
Pause(P) key operation
The Pause(P) key is designed to support pause operation in dialing duration. "P" key can be stored in memory
and it will occupy one digital position.
To select Pulse or Tone mode.
Off-hook(or turn on HF function), push (d1, d2,....dn,, P , k1, k2, ..... ,kn). These numbers will be dialed out
as following sequence :
d1, d2,.....dn, Tp, k1, k2, ..... ,kn (Tp are the pause Time)
SAVE redial memory
The SAVE memory is designed in EM91850 to support digits capacity buffer for second redial, pager, special
memory for memo and other system applications.
Storing : EM91850 support two operating methods to store numbers into SAVE redial memory.
Method 1 :
To select Pulse or Tone mode.
Off-hook(or turn on HF function), push d1, d2 ....., dn. The numbers d1, d2,..., dn will be dialed out in Pulse
or Tone mode as selection.
After dn had been dialed out and push [ST]. SAVE key. If the keying numbers are more than 32 digits that
content of SAVE memory can not be updated. Otherwise, these numbers will be stored into SAVE memory.
Noted : In the [ ] key allows to be omitted.
The SAVE buffer are the length 32 digits number
Method 2 :
On or Off-hook (or turn on HF function), push ST, d1, d2 ....., dn, [ST], SAVE. If the keying are not over 32 digits,
the numbers d1, d2, ....., dn will be stored in SAVE redial memory automatically.
Dialing
To select Pulse or Tone mode.
Off-hook(or turn on HF function or after executing Flash function), first push SAVE key. The numbers stored
in SAVE memory will be dialed out in Pulse or Tone mode as selection.
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