Specifications

48 Null Modem Cable Pin
Assignments
Table 48-1 outlines the pin assignments for a 9-pin serial port to a 25-pin serial port
null modem cable.
Note
All other pins on either connector of the cable are not
used.
Table 48-1 Null Modem Cable Pin Assignments
25 Pin 9Pin
2 (transmit data) 2 (receive data)
3(receivedata) 3(transmitdata)
4 (request to send) 8 (clear to send)
5 (clear to send) 7 (request to send)
6, 8 (data set ready, carrier detect) 4 (data terminal ready)
7 (ground) 5 (ground)
20 (data terminal ready) 6, 1 (data set ready, carrier detect)