Oh man, those were fun times. I started with a Model 15 TTY (for ham radio). When I got my first 8080 machine (statuc RAM was an expensive extra), I learned a lot by making a PC board to convert 45bps (5-bit characters) to 110bps Baudot (using 2 crystals). Then teaching the 8080 to table-convert baudot to ASCII (from a 'ring buffer' filled using interrupts).

The good old days, before layers of 'protection' got baked in (Apple II vs Mac).