PCMCIA cards are small extension cards for laptops. They were used around 1990.
PCMCIA cards are small (credit card sized) cards for laptops from around 1990. They are the equivalents of a connector to the old ISA bus. PCMCIA cards came in varying thickness, called type 1, type 2 and type 3.
PCMCIA was replaced by PCcard, which in turn was replaced by expresscard.