Synchronous/Asynchronous Communications Port
Table B–2 (Cont.) Synchronous/Asynchronous
Pin
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
1
international consultative committee that sets international communications
standards.
2
B–4 Port Pin-outs
Communications Port Pin-outs
Source
Signal
Modem/printer
CD
System
DTR
Modem/printer
RI
International Telegraph and Telephone Consultative Commiittee (CCITT), an
Electronic Industries Association
1
2
CCITT
EIA
Description
109
CF
Carrier detector
Not used
Not used
Not used
Not used
Not used
Not used
Not used
Not used
Not used
Not used
Not used
108.2
CD
Data terminal ready
Not used
125
CE
Ring indicator
Not used
Not used
Not used