Hello!

I bought a PC-jr for \pounds 10.00 (about $15) at a radio rally (hamfest) last month. It was complete with the chicklet keyboard, but alas the transformer unit (mains in, 17V AC out) was missing. I 'phoned IBM, and amazingly the technical reference was still available, and cost \pounds 45-ish. So I ordered it. It's a very good manual, with schematics of the motherboard, RAM card, modem, disk controller, IR receiver, modem (the only option I don't have), printer port, ROM cartridge, PSU, CGA monitor, etc. There's also a commented source of the ROM BIOS, and (appropriate to the above question) the format of the IR keyboard data. The keyboard schematic is not in the manual, and nor is the source code for the 80C48 microcontroller in the keyboard. But it should be possible to use another IR transmitter with the PC-jr (or converserly to use the PC-jr keyboard with another machine).