apple II - PS/2
            - RS232 -keyboard interface

Built Up Kit - Configured for the Apple II

ASCII to PS/2 Keyboard Adapter

This board converts either a PS/2 keyboard input or RS232 input into a ASCII keyboard interface.  It has been tested with the Apple 1 and Apple II models, but other vintage computers that take a parallel ASCII keyboard interface should work.  Apple IIe and later Apple computers will not work with this interface.   See my blog or video podcast for more information.

Version 3.0 Firmware Changes

In order to allow support of different styles of ASCII parallel keyboard interfaces, options for additional styles of strobe handling has been added.   In addition to disabling control-RST and control-CLR functionality, inserting the CR jumper also causes the SRB output pulse to be maintained until CLR, which becomes an input, is asserted (high). When the CR jumper is inserted, connecting SRB output directly to CLR input, will result in the normal 125 micro-second pulse. If you connect the SRB output directly to CLR input with an appropriate resistor (say 10K) and connect the CLR input to ground with an appropriate value capacitor (say .1uF), you create a RC timing circuit which can be used to extend SRB. The aforementioned values will extend strobe to 1 millisecond, but other values can be used to set the timing to a value that you desire. With the CR jumper inserted, the CLR TTL input can also be connected to external logic which can terminate SRB in any arbitrary fashion.


Download Source and HW Files

I no longer sell kits or boards, but you can download the assembler source and hardware CAD files and build your own PS/2 adapter.

Before you download, understand that you will be on your own and assume all risks associated with this project.

Software Files:
Hardware Files:

This Project was Inspired by Other Peoples Work

  keyboard adaptor connected
First Prototype Adapter Hooked Up to an Apple II on One End - a PS/2 Keyboard and a PC via RS232 on the Other

Questions: send an email

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