An ASCII Serial keyboard

An ASCII Serial keyboard using a Picaxe 08M

This home-made keyboard was used in the 80's with a home-built terminal which was used at my work with a Radio Shack XENIX computer, which used 8" floppies and a 10 megabyte drive!
Of course, the computer and terminal is long gone but I couldn't bear to scrap the keyboard because of the lovely mahogany case. Besides, it uses high-quality hall-effect keyswitches.
The keyboard originally had no additional circuitry, being connected by parallel wires to the terminal. Later it was equipped with shift registers and a Picaxe 18.
A third modification in 2008 was to use a Picaxe 08M which was an improvement.
Now, in 2022, it is slightly changed again to perform as a controller for my home autmation, using an external RF 433 MHz transmitter.
The output is RS-232 Serial at 2400 baud with the necessary format required for the RF link.
The code includes an option selected by the Del and Break keys to switch between command and display transmit formats.

This is the program

This is the circuit diagram