IBM RT Series Hardware Reference Manual page 457

Parallel Interface
The adapter has a 2S-pin, D-shell connector at the rear of the
adapter. The following figure shows the signals and their pin
assignments. Typical printer input signals also are shown.
Elt~rna
Device
-
I
-
-
-
- Strobe
Data Bit 0
Data Bit 1
Data Bit 2
Data Bit 3
Data Bit 4
Data Bit 5
Data Bit 6
Data Bit 7
- ACK
8USY
PE
SLCT
- AUTO FEED XT
- ERROR
-INIT
- SLCT IN
Ground
1
2
3
4
5
6
7
8
9
10
11
12
13 ..
14
15
16
17
18-25
-
I - -
Serial
Parallel
Adapter
Serial/ParaDel Adapter 23