Comtrol UP DeviceMaster Installation - Manual (Page 51)

Hardware Installation and Configuration Guide: 2000451 Rev. J Connecting Serial Devices - 51
Connecting Serial Devices
Serial Terminal (8)
Null-Modem Cables
(RS-422) An RS-422 null-modem cable is
required for connecting DTE
devices.
Serial Terminal (8)
Straight-Through
Cables (RS-232/485) RS-232 or RS-485 straight-
through cables are used to
connect modems and other
DCE devices.
Serial Terminal (8)
Loopback Signals Use the drawing below to wire a loopback, which is used in conjunction with
application software to test serial ports.
Wire the terminals together to
create a loopback.
• TxD to RxD
• RTS to CTS to RI
• DTR to CD to DSR
CD DSR RI DTR RTS TxD RxD CTS
RxD+ RxD- TxD- TxD+
8 2 3 7
5 3 2 4
DB9
DB25
RS-422 Null-Modem Cable
RS-232/485 Straight-Through Cable
CD DSR RI DTR RTS TxD RxD CTS
DCD DSR RI DTR RTS TxD RxD CTS
1 6 9 7 2 8
6 22 20 4 2 3 5
DB9
DB25
3 4
8
or
TRxD-
or
TRxD+
TxD RxD RTS CTS CD DSR RI DTR