The 8255 / 8254 laboratory adapter is a programmable peripheral interface for PC/XT, PC/AT, 80386, 80486, Pentium or compatible computer. The interface card contain 8254 chips and 8255 chips, the 8254 chips provide programmable interval timer/counter functions and the 8255 chips provide programmable input/output functions. There are two types of cards, one contains many plated through-holes at the adapter for laboratory development and another is the typical 8255/8254 adapter.

Features of the 8255/8254-laboratory card
*Programmable I/O control functions.
*Up to 48 I/O lines.
*Maximum of 10MHZ count rate.
*Three independent 16 bits counter.
*Support several operating modes that are programmable.
*Port address selectable.