User`s guide

Appendix A TECHNICAL INFORMATION
The Technical Information Appendix includes the
following information:
• Keyboard interface information describing the
5-pin DIN connector.
• Overview of how scan codes are processed.
• IBM PC/XT™ and AT* scan code charts.
• Specifications for the KB 101 keyboard.
Keyboard
Interface
Information
Communications between the keyboard and host
computer occur through a shielded keyboard cable. The
cable end has a 5-pin DIN connector that attaches to the
receptacle located on the rear panel of the computer.
The cable contains a logic ground line, power line, and
bi-directional clock and data lines. Data I/O uses
synchronous, serial protocol.
An illustration of the 5-pin DIN connector and a table
showing the function and signal or voltage of each pin is
shown below.
Pin
1
2
3
4
5
Function
Clock
Data
Not used
Ground
Power
Signal/
Voltage
TTL
TTL
OVdc
-1-5 Vdc
Keyboard
Connector
x-^
1 [ • •)3
Kj^.
2
5-pin DIN
Connector
Page A-1