Definition: ISA bus

(Industry Standard Architecture bus) An earlier hardware interface for connecting peripheral devices in PCs. Pronounced "eye-suh," ISA accepted cards for sound, display, hard drives and other devices. Originally called the "AT bus" and introduced with the IBM PC AT in 1984, the AT/ISA bus extended the PC bus from 8 to 16 bits. For several years, motherboards provided a mix of both 8-bit and 16-bit ISA slots. As PCI became popular, motherboards included only 16-bit ISA and PCI, and by the early 2000s, ISA was being replaced entirely by the PCI interface. See PC data buses and PCI.




ISA Slots






Mixed ISA Slots






Earlier Expansion Cards