The 16-bit bus started with the IBM-AT (Advanced Technology) systems. It is still the standard interface for most PC expansion cards. It is also known as the ISA (Industry Standard Architecture) bus.

n. The electric pathway used by IBM AT and compatible computers to connect the motherboard and peripheral devices. The AT bus supports 16 bits of data, whereas the original PC bus supports only 8 bits. Also called expansion bus. See also EISA, ISA, Micro Channel Architecture.

The common communication channel in a PC AT. The channel uses a 16-bit data path architecture, which allows up to 16 bits of data transfer. This bus architecture includes the standard PC bus plus a set of 36 lines for additional data transmission, addressing, and interrupt request handling.

See IDE.