Db9 Null-Modem Cables (Rs-232); Db9 Null-Modem Cables (Rs-422); Db9 Straight-Through Cables (Rs-232/485) - Comtrol DeviceMaster Up Hardware Installation Manual

DB9 Null-Modem Cables (RS-232)

DB9 Null-Modem
Cables (RS-232)
DB9 Null-Modem
Cables (RS-422)
DB9 Straight-
Through Cables (RS-
232/485)
28 - DeviceMaster UP User Guide: 2000451 Rev. C
Use the following figure if you need to build an RS-232 null-modem cable. A null-
modem cable is required for connecting DTE devices.
Signal
TxD
RxD
RTS
CTS
DSR
DCD
DTR
GND
Note: You may want to purchase or build a straight-through cable and purchase a
null-modem adapter. For example, a null-modem cable can be used to
connect COM2 of one PC to COM2 of another PC.
Use the following figure if you need to build an RS-422 null-modem cable.
Note: RS-422 pinouts are not standardized. Each peripheral manufacturer uses
different pinouts. Please refer to the documentation for the peripheral to
determine the pinouts for the signals above.
Use the following figure if you need to build an RS-232 or RS-485 straight-through
cable. Straight-through cables are used to connect modems and other DCE
devices. For example, a straight-through cable can be used to connect COM2 of one
PC to COM2 to a modem.
Signal
DCD
RxD
TxD or TRx-
DTR
GND
DSR
RTS or TRx+
CTS
RI
DB9
DB9
Pins
Pins
3
2
2
3
7
8
8
7
6
4
1
1
4
6
5
5
DB9
Signal
Pins
TxD+ 7
TxD- 3
RxD+ 8
RxD- 2
DB9 DB9 RJ45
Pins Pins Pins
1 1 6
2 2 5
4
3 3
4 4 2
5 5 3
6 6 7
1
7 7
8 8 8
9 N/A
9
DB25
RJ45
Pins Signal
Pins
RxD
3
5
TxD
2 4
CTS
5 8
RTS
4
1
DTR
20
2
DCD
8
6
DSR
6 7
GND
7
3
Signal
RxD+
RxD-
TxD+
TxD-
DB25
Pins Signal
8
DCD
3
RxD
2
TxD or TRx-
20
DTR
7
GND
6
DSR
4
RTS or TRx+
5
CTS
22 RI
Connecting Serial Devices