Serial Interface Pin Definitions - 3Com 56k User's Manual And Reference

Serial Interface Pin Definitions

DB-25 DB-9
1 —
2 3
3 2
4 7
5 8
6 6
7 5
8 1
12 —
20 4
22 9
74
Technical Reference
Circuit Function
AA Chassis Ground
BA Transmitted Data
BB Received Data
CA Request to Send
CB Clear to Send
CC Data Set Ready
AB Signal Ground
CF Carrier Detect
SCF Speed Indicate
CD Data Terminal Ready
CE Ring Indicate
Signal Source
Computer/Modem
Both
Computer
Modem
Computer
Modem
Modem
Both
Modem
Modem
Computer
Modem