Document No. 422PP9R4300 - pg. 1/2
B&B Electronics -- Revised November 2000
This product designed and manufactured in USA of domestic and imported parts by
Port Powered RS-232 to RS-422 Converter
CE
CE
CE
CE
Model 422PP9R
The 422PP9R is a port-powered, two-channel RS-232 to RS-422
converter. It converts TD and RD RS-232 lines to balanced RS-422 signals.
The unit is powered from the RS-232 handshake lines DTR and RTS. Only
one of these lines must be present, and the unit will work regardless of
whether the lines are high or low. Both the RS-422 driver and receiver are
enabled at all times.
To satisfy the requirements of some software, the RS-232 handshake
lines are looped back (tied together). RTS is connected to CTS, and DTR is
connected to DCD and DSR.
Connections
The 422PP9R is configured to transmit both directions between an RS-232 and RS-422 system. The RS-232 side is
pinned out to connect directly into the COM port on your computer or any other DTE device (Table 1). The RS-422 side of
the converter is pinned out as described in Table 2. When connecting to a RS-422 system, the 422PP9R must be
connected with the proper polarity as shown in Figure 1. When no data is being sent the RS-232 line is negative and the
RS-422 line TD(A) is negative with respect to TD(B).
Figure 1 - Connection to an RS-422 System
8
3
2
7
4
T D (A )-
T D (B )+
R D (A )-
R D (B )+
G N D
G N D
R D (A )-
T D (A )-
R D (B )+
T D (B )+
4 2 2 P P 9 R
D B 9 fe m a le
R S -4 2 2
Table 1 - RS-232 Pin Out
Signal
DB9 female
Pin #
TD
3
RD
2
RTS
7
CTS
8
DTR
4
DSR
6
DCD
1
GND
5
Table 2 - RS-422 Pin Out
Signal
DB9 female
Pin #
TD A (-)
8
TD B (+)
3
RD A (-)
2
RD B (+)
7
GND
4, 6
Document No. 422PP9R4300 - pg. 2/2
B&B Electronics -- Revised November 2000
This product designed and manufactured in USA of domestic and imported parts by
Biasing Resistors
The biasing resistors for the RS-422/RS-485 receiver are 4.7k Ohm resistors. These resistors are labeled R1 and R2
(See Figure 2). Refer to B&B Electronics RS-422/485 Application Note for further information on biasing.
Figure 2
+ 5 V
D C D
1
3
2
5
T D
G N D
R D
R 2
7
8
4
6
C T S
D T R
D S R
R T S
C irc u it
P o w e r
C o n v e rsio n
R 1
4 .7 k
T D (B )+
T D (A )-
R D (B )+
R D (A )-
G N D
3
8
7
2
4
4 .7 k
R S -2 3 2
D B 9 fe m a le
R S -4 2 2
D B 9 fe m a le
Specifications
Communication:
RS-422
Data Rate:
115.2 kbps max.
Power:
Port-Powered from handshake lines on the RS-232 side.
Dimensions:
6.1 x 3.3 x 1.7 cm (2.4 x 1.3 x 0.66 in)
Temperature Rating:
0 to 70C
NOTE: When using an external supply, the supply should be connected only to specifically labeled power inputs
(power jack, terminal block, etc.). Connecting an external power supply to the handshake lines may damage the
unit. Contact technical support for more information on connecting an external power supply to the handshake
lines.
DECLARATION OF CONFORMITY
Manufacturer's Name:
B&B Electronics Manufacturing Company
Manufacturer's Address:
P.O. Box 1040
707 Dayton Road
Ottawa, IL 61350 USA
Model Numbers:
422PP9R
Description:
9-Pin Port-Powered RS-422 Converter
Type:
Light industrial ITE equipment
Application of Council Directive: 89/336/EEC
Standards:
EN 50082-1 (IEC 801-2, IEC 801-3, IEC 801-4)
EN 50081-1 (EN 55022, IEC 1000-4-2)
EN 61000 (-4-2, -4-3, -4-4, -4-5, -4-6, -4-8, -4-11)
ENV 50204
EN 55024
Michael J. Fahrion, Director of Engineering
PDF 
ZIP