IBM 5150 PC Technical Reference (6025005, August, 1981) (PDF)

Asynchronous Communications Adapter Connector
Interface Specifications
REAR PANEL
/""\ \\
External
Device
_OCZ5
o
~ 0~
AT STANDARD TTL LEVELS
Description
...
....
... ,
NC
Transmit Data
Receive Data
Request to send
Clear to send
Data set ready
Signal ground
Carrier detect
... +Transmit current loop return (20 rna)
~
NC
....L
....
-Transmit current loop data (20 rna)
NC
NC
NC
NC
NC
NC
+Receive current loop data (20 rna)
NC
Data Terminal Ready
NC
Ring Indicate
NC
NC
- Receive current loop return (20 rna)
Pin
1
2
3 ..
4
5
..
r'
6
..
7
8
..
9
0
• 25
• •
•
•
• • 14
•
0
10
11
Asynchronous
12
Communications
13 Adapter
14 (RS232C)
15
16
17
18 ...
19
20
21
22
23 •
24
25 ..
..
NOTE:
To avoid inducing voltage surges on interchange circuits, signals from interchange
circuits shall not be used to drive inductive devices, such as relay coils.
2-147