RS-232 Pinouts
2
Product Overview
RS-232
DB9 Female
Connector
(DCE)
Model 4WSD9TB
RS-232
DB25 Female
Connector
(DCE)
RS-422/485
Terminal
Block
Configuration
Switch
RS-422/485
DB9 Female
Connector
External 12VDC
Power Jack
Model 4WSD9R
External 12VDC
Power Jack
Getting Started
1
Models 4WSD9R & 4WSD9TB convert RS-232 signals to
RS-422/RS-485 and vice versa. RS-232 TD signals are
converted to balanced RS-422 or RS-485 signals. RD RS-
422/485 signals are converted to RS-232.
Table 2. RS-422/485 PINOUT
PIN #
SIGNAL
2
RD (A)-
3
TD (B) +
4
GND
6
GND
7
RD (B)+
8
TD (A)-
Table 1. RS-232 PINOUT
PIN #
SIGNAL
1
DCD
2
RD
3
TD
4
DTR
5
GND
6
DSR
7
RTS
8
CTS
RS-422-RS-485
3
Automatic Send Data Control
5
Unlike converters that require programming the hardware
handshake signals to control RS-422/RS-422 operation,
Models 4WSD9TB or 4WSD9R provide Automatic Send
Data Control, enabling the driver only when transmitting:
In RS-485 Modes
, the RS-485 driver is enabled by
circuitry which senses the RS-232 TD Input.
In RS-485 Half-Duplex Mode
, the receiver is enabled
when not transmitting (Echo Off).
In RS-485 Full-Duplex Mode
, the receiver is always
enabled.
In RS-422 Full-Duplex Mode
, the transmitter and
receiver are always enabled.
Table 3. SWITCH SETTINGS
RS-485 2-Wire Half-Duplex
SWITCH #
POSITION
1
RS-485
2
Echo Off
3
2-wire
4
2-wire
Table 4. SWITCH SETTINGS
RS-485 4-Wire Full-Duplex
SWITCH #
POSITION
1
RS-485
2
Echo On
3
4-wire
4
4-wire
Table 5. SWITCH SETTINGS
RS-422 4-Wire Full-Duplex
SWITCH #
POSITION
1
RS-422
2
Echo On
3
4-wire
4
4-wire
DIP Switch Settings
6
Mode Wiring Examples
4