Specifications

72 PCI-Comm Card Series User's Manual
Modem connections
DB-25 Male Modem (DCE)
Pin Signal Pin Signal
2 TxD 2 RxD
3 RxD 3 TxD
4 RTS 4 CTS
5 CTS 5 RTS
6 DSR 6 DTR
7 GND 7 GND
20 DTR 20 DSR
8 DCD 8 DCD
For DTE to DCE connections, use straight through cable (i.e., you
don't have to reverse lines 2 and 3, lines 4 and 5, and lines 6 and 20
since, in general, the DCE RS-232 interfaces are reversed themselves).
Terminal without handshake
DB-25 Male Terminal, PC (DTE)
Pin Signal Pin Signal
2 TxD 3 RxD
3 RxD 2 TxD
4 RTS —
5 CTS —
7 GND 7 GND
6 DSR —
20 DTR —
8 DCD —
Therefore, if you are not using CTS, RTS, DSR ,DTR and DCD
signals, please short pins 4 and 5 together, and please short pins 6, 8,
and 20 together.