HP262x keyboard voltage

I don't think I have one of those. What machine does it go with? No, the HP9816 keyboard is very different. it's a 5V interface on 4 wires (+5V, ground, clock, data (from keyboard)/reset (to keyboard). It also has the twiddleknob (which is addressed as 1 column of keys -- 7 bits of motion and 1 of direction IIRC). Interestingly the 9816 keysiwtches are not wired as a matrix, rather one side of each switch is grounded, the other goes to a multiplexer input. Scheamtics are on hpmuseum.net. The closest keyboard i have electrically is the HP150 one. It is the same interface, similar circuitry, but with differnt key matrix layout. I think I can hackl that by replacing the scan counter chip in the keyboard (a 4024) with a little circuit of about half a dozen chips. The closest keyboard I have for having the right keys is the one for the HP2623 terminal -- after all a similar keyboard was used on the HP125, which as you know is a very similar machine to the HP120 (to the extent that the firmware ROMs are the same, for example). Of course the interface is quite differen, but a conversion circuit shouldn't be too hard to buiold (probably cost more for case/connectors than for logic chips!). -tony