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38 - Connecting Serial Devices
DeviceMaster PNIO | UP User Guide
: 2000639 Rev. A
Connecting Serial Devices
DB9 Connectors
This subsection provides the following information:
•
Connector pin assignments (below)
•
DB9 Null-Modem Cables (RS-232)
•
DB9 Null-Modem Cables (RS-422)
•
DB9 Straight-Through Cables (RS-232/485)
•
•
Refer to the hardware manufacturer’s installation documentation if you need help
with connector pinouts or cabling for the serial device. This illustrates the DB9
connector signals.
DB9 Connector Pinouts
Pin RS-232
RS-422
RS-485 Full-Duplex
(Master/Slave)†
RS-485
Half-Duplex
1
DCD
Not used
Not used
2
RxD
RxD-
Not used
3
TxD
TxD-
TRxD-
4
DTR
Not used
Not used
5
GND
GND
GND
6
DSR
Not used
Not used
7
RTS
TxD+
TRxD+
8
CTS
RxD+
Not used
9
RI
Not used
Not Used
†
The following models support RS-485 full-duplex:
•
1-Port DIN rail models
•
2-Port DIN rail models
•
4-Port DIN rail models
Pin 1
Pin 6
DB9 Male
RS-232
RI
CTS
RTS
DSR
GND
DTR
TxD
RxD
CD
Pin 1
Pin 6
DB9 Male
RS-422
Not used
RxD+
TxD+
Not used
GND
Not used
TxD-
RxD-
Not used
Pin 1
Pin 6
DB9 Male
RS-485
Not used
Not used
TRxD+
Not used
GND
Not used
TRxD-
Not used
Not used