IBM Personal System/2 CL57 SX - External Input Device Connector

1.2.7 External Input Device Connector
The external input device connector is located at the rear of the system
and accepts a mouse or 17-key numeric keypad. The Model CL57 SX has only
one input-device connector. However, it is possible to connect the
numeric keypad and the mouse at the same time through another input-device
connector located at the rear of the numeric keypad.
The integrated trackball does not work when the mouse is connected.
IBM PS/2 Model CL57 SX HMR
External Input Device Connector
_ Copyright IBM Corp. 1991
1.2.7 - 1