This hand made PC ISA slot interface card used the 8255 chip to provide three 8 bit digital i/o ports. The DIP switch is part of setting the address of the card. A 25 pin (D sub) cable connected the card to an experimenter card made using the same wire wrap technology as the interface card.
These experimenter boards gave the students 8 LEDs, a 7 segment display, 8 DIP switches mounted on the white header and access to 8 i/o pins via the terminal strip to connect external circuits and experiments.
Part 3 shows some interface circuits and other random circuits made in the 90s.