Appendix C. Cables
C–22
Table C–13. DCE RS-449 Pin Assignments
MCS
Network
26-Pin
Description
Function
37-Pin
1
Protective ground
FG
1
2
Send data A
SD (A)
4
11
Send data B
SD (B)
22
3
Receive data A
RD (A)
6
12
Receive data B
RD (B)
24
4
Request to send A
RTS (A)
7
13
Request to send B
RTS (B)
25
5
Clear to send A
CS (A)
9
14
Clear to send B
CS (B)
27
6
Data mode A
DM (A)
11
15
Data mode B
DM (B)
29
7
Signal ground
SG
19
8
Receiver ready A
RR (A)
13
17
Receiver ready B
RR (B)
31
9
Terminal ready A
TR (A)
12
18
Terminal ready B
TR (B)
30
10
Local loopback
LL
10
19
Send timing A
ST (A)
5
20
Send timing B
ST (B)
23
21
Receive timing A
RT (A)
8
22
Receive timing B
RT (B)
26
23
Terminal timing A
TT (A)
17
24
Terminal timing B
TT (B)
35
The remaining pins are not used.
