Db9 connector pinouts, Building null-modem cables, Building null – Comtrol RPSH-ia User Manual
Page 7: Modem cables
RocketPort® Serial Hub ia (RPSH-ia) Hardware Installation
7
DB9 Connector Pinouts
DB9 Connector Pinouts
Use the following pinout information for the DB9 serial port
connectors on the RocketPort Serial Hub ia.
Building Null-Modem Cables
Use the following figure if you need to build a null-modem cable. A null-modem
cable is required for connecting DTE devices.
Note: You may want to purchase or build a straight-through cable and purchase a
null-modem adapter.
Pin
RS-232
RS-422
RS-485
1
CD
Not used Not used
2
RxD
RxD-
Not used
3
TxD
TxD-
TRX-
4
DTR
Not used Not used
5
GND
Not used Not used
6
DSR
Not used Not used
7
RTS
TxD+
TRX+
8
CTS
RxD+
Not used
9
RI
Not used Not used
Pin 1
Pin 5
Pin 6
Pin 9
DB9 Male
RPS
H
-ia
Connect
or
TxD
RxD
RTS
CTS
DSR
GND
DCD
DTR
Signal
RxD
TxD
CTS
RTS
DTR
GND
DCD
DSR
Signal
DB9
2
3
8
7
4
5
1
6
Pins
DB25
3
2
4
7
8
6
Pins
R
e
m
o
te an
d
RP
SH
-ia
DB9
3
2
7
8
6
5
1
4
Pins
20
5
Fe
m
a
le
Connect
ors
RI
9
9
22
RI