User`s guide

C. Connectors, Cables, and Pin Assignments
C-8
May 2002 7990-A2-GB20-00
Table C-5. X.21 Cable Interface
Signal
ITU-T
Number Direction
Pin
Number
Signal Common 102 — 8
Transmitted Data 103 To DSU/CSU 2 (A)
9 (B)
Received Data 104 From DSU/CSU 4 (A)
11 (B)
Request to Send 105 To DSU/CSU 3 (A)
10 (B)
Data Channel Received Line Signal Detector 109 From DSU/CSU 5 (A)
12 (B)
Transmit Signal Element Timing (DTE Source) 113 To DSU/CSU 7 (A)
14 (B)
Receiver Signal Element Timing (DCE Source) 115 From DSU/CSU 6 (A)
13 (B)