Test equipment using an IR IC for the keyboard

[Scratch.HTF]

I've seen certain pieces of test equipment with a keyboard which uses an infrared remote transmitter IC (or other serial transmitter) which has a single unidirectional data line to send a key code to the microcomputer section.
Do you know of any other pieces of test equipment which has the above characteristics?
Such examples of equipment I have seen are the Philips PM5193 function generator, Philips PM551x/PM541x TV pattern generators, and the Katherin MFK85 TV/radio signal meter (I've added IR remote functionality to my PM5193 and PM551x!)