IBM 21Y Maintenance Manual page 51

System board external port connectors
The following illustration identifies system-board connectors
for external devices.
1
Keyboard/mouse
2
USB
3
Serial A
4
Parallel
5
Serial B
6
Ethernet
7
Video
System board switches and jumpers
The following illustration shows the switches and jumpers on
the system board.
42
Netfinity 3500-M20 – Type 8657 Models 21Y, 22Y, 31Y, 32Y,