A type of connection port inside a personal computer into which a circuit board, commonly called an expansion card, can be installed. The expansion slot is lined with a row of electrical contacts, which mate with similar contacts on the expansion card. In the audio world, expansion slots are often used for expansion cards that provide various types of digital and analog audio input and output, as well as extra DSP processing power and other capabilities that enhance the computer’s own power.
Several formats for expansion slots have been used over the years, including AGP, Nubus, and ISA, with the current standard being PCI, which was first introduced in 1991 by Intel. Laptops may use PCMCIA or the more current ExpressCard or CardBus formats.