Universal I/O interface for IBM PCs
Those were the days when you could use your Commodore C64,
Acorn Atom or 2x81 computer to control hardware intelligently.
Model train systems, robots, greenhouse watering and temperature
control systems -all within easy reach of the keen programmer
with little or no knowledge of computer hardware. Alas, the coming
of the IBM PC, the compatibles, the ATs and the 386-based systems,
seems to have banished simple hardware interfacing, the PC being
an expensive 'box' harnessing a lot of computing power, but
restricted to use in an office environment. We do not agree that a PC
is unsuitable for control applications: all it needs is the circuit
described here: a low-cost fully buffered insertion card that forms a
versatile, simple and safe link between the PC (whether an XT, AT or
386-based machine) and your own hardware.