7970-A2-GB20-00
Table C-7. RS-449 Cable Interface
Signal
Shield
Signal Ground
Receive Ground
Send Common
Send Data
Receive Data
Request to Send
Clear to Send
Receiver Ready
Data Mode
Terminal Ready
Terminal Timing
Send Timing
Receive Timing
Local Loopback
Remote Loopback
Test Mode
August 1999
Cables and Pin Assignments
Circuit
ITU-T
Mnemonic
Number
—
—
SG
102A
RC
102B
SC
—
SD
103
RD
104
RS
105
CS
106
RR
109
DM
107
TR
108/1, /2
TT
113
ST
114
RT
115
LL
141
RL
140
TM
142
Direction
Pin
—
1
—
19
—
20
—
37
To DSU/CSU
4 (A)
22 (B)
From DSU/CSU
6 (A)
24 (B)
To DSU/CSU
7 (A)
25 (B)
From DSU/CSU
9 (A)
27 (B)
From DSU/CSU
13 (A)
31 (B)
From DSU/CSU
11 (A)
29 (B)
To DSU/CSU
12 (A)
30 (B)
To DSU/CSU
17 (A)
35 (B)
From DSU/CSU
5 (A)
23 (B)
From DSU/CSU
8 (A)
26 (B)
To DSU/CSU
10
To DSU/CSU
14
From DSU/CSU
18
C-11