Programmable Peripheral Interface I/O Controller Board for PC 16 bit ISA bus (1994)

The printed circuit board was manually designed with SmartEdit to withstand industrial conditions, communicating optically with external electronic circuitry by means of 6 replaceable 4 bit bidirectional configurable opto-couplers.
Three programmable I/O ports (Sub D 9 pin connectors) communicating with the outside world are optically separated to prevent the host computer potentially from being damaged in case the I/O connector wiring would accidentally be cut and shortcut-ed causing an electric surge e.g. a forklift or falling heavy materials.

This I/O controller was used to contol things like an infrared target-lock robotic arm, sound recording (ADC) & distance measuring with piezoelectric ultrasonic probes (DAC / ADC).

Unfortunately the ISA bus is no longer present in PC's

 Sub D (9 pin) connectors (vcc, mass, 8 bit data)

 The heart: A Programmable I/O CTRL (8255AC)
10 bit I/O Addressable (Default port: 0x12C (hex)

Bidirectional Optical Data Transmission (ILQ74)