Connectors, Cables, and Pin Assignments
C-14 9820-A2-GB20-20June 2000
The following table provides the pin assignments for the DB25-to-DB25
straight-through cable.
Signal ITU #
25-Pin
Plug
Pin # Direction
25-Pin
Socket
Pin #
Shield — 1 1
Transmit Data (TXD) 103 2 (A)
14 (B) To DCE 2 ( A)
14 (B)
Received Data (RXD) 104 3 (A)
16 (B) From DCE 3 (A)
16 (B)
Request to Send (RTS) 105 4, 19 To DCE 4, 19
Clear to Send (CTS) 106 5, 13 From DCE 5, 13
Data Set (or DCE) Ready (DSR ) 107 6 From DCE 6
Data Terminal (or DTE) Ready
(DTR) 108/1, /2 20 To DCE 20
Signal Ground/Common (SG) 102 7 7
Data Channel Received Line
Signal Detector (RLSD or LSD) 109 8, 10 From DCE 8, 10
Transmit Signal Element Timing
(TXC) — DCE Source 114 15 (A)
12 (B) From DCE 15 (A)
12 (B)
Received Signal Element Timing
(RXC) — DCE Source 115 17 (A )
9 (B) From DCE 17 ( A)
9 (B)
Local Loopback (LL) 141 18 To DCE 18
Loopback/Maintenance (RL) 140 21 To DCE 21
Transmit Signal Element/
Terminal Timing (TT) —
DTE Source
113 24 (A )
11 (B ) To DCE 24 ( A)
11 (B )
Test Mode Indicator (TM) 142 25 From DCE 25