System information

Reference Guide Crestron 2-Series Control System
84 • 2-Series Control Systems Reference Guide – DOC. 6256A
Cable Requirements (2-Series Control System to
Modem)
The cable used to connect a 2-Series processor’s RS-232 computer port to a modem
is a standard DB9 female to DB25 male with a null modem adapter attached. The
null modem adapter can either be DB9F-DB9M or DB25F-DB25M. These parts are
commercially available and do not require custom fabrication.
The pin assignments for the DB9 male-to-DB25 male straight-through cable are
listed in the following table:
Pin Assignments for DB9 Male-to-DB25 Male Straight-Through Cable
DB9 MALE DB25 MALE
PIN NAME PIN NAME
1 CD 8 CD
2 RX 3 RX
3 TX 2 TX
4 DTR 20 DTR
5 Ground 7 Ground
6 DSR 6 DSR
7 RTS 4 RTS
8 CTS 5 CTS
9 RI 22 RI
The pin assignments for the DB9 female-to-DB25 male straight-through cable are
listed in the following table:
Pin Assignments for DB9 Female-to-DB25 Male Straight-Through Cable
DB9 FEMALE DB25 MALE
PIN NAME PIN NAME
1 CD 4 DTR
2 RX 3 TX
3 TX 2 RX
4 DTR 1 CD
4 DTR 6 DSR
5 Ground 5 GND
6 DSR 4 DTR
7 RTS 8 CTS
8 CTS 7 RTS
9 RI - N/A
- N/A 9 RI