IBM PS/1 User Manual

AT Expansion Bus (Riser)
Note: Pin A is the system board pin. Pin B is the riser card pin.
Pin
A
Signal
Name
Pin
B
I/O
1 +12 V dc B9
2 +5 V dc
3 Ground
4 Ground B1
5 Reset Drv B2 O
6 +5 V dc B3
7 IRQ9 B4 I
8 −5 V dc B5
9 DRQ2 B6 I
10 −12 V dc B7
11 OWS B8
12 +12 V dc B9
13 Ground B10
14 SMEMW B11 O
15 SMEMR B12 O
16 IOW B13 I/O
17 IOR B14 I/O
18 DACK3 B15 O
19 DRQ3 B16 I
20 DACK1 B17 O
21 DRQ1 B18 I
22 Refresh B19 I/O
23 System
Clock
B20 O
24 IRQ7 B21 I
25 IRQ6 B22 I
26 IRQ5 B23 I
27 IRQ4 B24 I
Parts/Test Point Locations 5-25

IBM PS/1 Specifications

General

Processor	Intel 80286 or 80386
Processor Speed	10 MHz (80286)
RAM	1 MB (expandable to 2 MB or more)
Storage	40 MB hard drive
Floppy Drive	3.5" 1.44 MB
Graphics	VGA
Ports	Serial, Parallel, Mouse