The 6526/8520 Complex Interface Adapter (CIA) was an integrated circuit made by MOS Technology.

I/O was provided by two MC6821 Peripheral Interface Adapters (PIAs).

The interface is implemented by an AMD 7992 SIA (Serial Interface Adapter) and a BNC ThinWire connector.

A Virtual Interface Adapter ("VIA") is a network protocol (such as TCP/IP ...).

The Peripheral Interface Adapter (PIA) is a peripheral integrated circuit providing parallel I/O interfacing capability for microprocessor systems.

The Peripheral Interface Adapter had a slight change in the electrical characteristics of the I/O pins so the MC6820 became the MC6821.

The W65C21S is a very flexible Peripheral Interface Adapter (PIA) for use with WDC's 65xx and other 8-bit microprocessor families.

This capability provides enhanced control over data transfer functions between the microprocessor and peripheral devices, as well as bidirectional data transfer between W65C21S Peripheral Interface Adapters in multiprocessor systems.

All Amiga computers use two 8520 CIAs (Complex Interface Adapter) for peripheral interfacing and the system timers.

Inside the computer, the first Complex Interface Adapter (6526) in the C64 senses when the signal goes from one to zero.