ISA bus(Pronounced as separate letters or as eye-sa). Short for Industry Standard Architecture bus, the bus architecture used in the IBM PC/XT and PC/AT. The AT version of the bus is called the AT bus and became a de facto industry standard. Starting in the early 90s, ISA began to be replaced by the PCI local bus architecture. Most computers made today include both an AT bus for slower devices and a PCI bus for devices that need better bus performance.
In 1993, Intel and Microsoft introduced a new version of the ISA specification called Plug and Play ISA. Plug and Play ISA enables the operating system to configure expansion boards automatically so that users do not need to fiddle with DIP switches and jumpers.