GPIB (was Re: OT: Windows profanity)

If you're just talking to 1 or 2 peripherals (say you want to hook up a GPIB plotter, or you want to get the data off an HP disk drive) you can get away without the special buffers. You can use open-collector TTL gates to drive the bus, and TTL schmitt triggers ('14s, for example) as receivers. Like many things I'd not do this on a 'production' board, but it works as a hack. You don't ened a GPIB talker/listener/controller IC. The whole bus is designed so that the handshakes are 'interlocked' That is, something happening in one device causes some other device to do something, then the first deivce might do something else, etc. You can do the whole handshake in software (Commodoer always did, in the PET and all the peripherals), and there's no chance of missing a signal transition. Alternatively you can make some state machines from TTL or PALs (I did this years ago, it's not hard) if you like hardware. I have plenty of GPIB-capable machines from handheld calculators up to workstations (e.g. HP41 + HPIL + HP82169 translator in the first case, PERQ in the second). I even have the Acorn interface for the Beeb. Nothing spare, though Yes, 24 pin Blue Ribbon. Watch out, the screw-down jackposts have the M3.5 thread, and as far as I know are unobtainium from any of the normal UK catalogues. I had to spend an hour in the garage making some from stainless steel rod... -tony