A hardware interface specifies the plugs, sockets, cables and electrical signals that pass through each line between the CPU and a peripheral device or communications network. It also stipulates which data trigger which functions, and the control software that "drives" the hardware is also part of the hardware interface (see
driver).
Motherboards
The CPU socket on the motherboard determines which CPU chips can be used in the computer. Peripheral cards, such as high-end graphics cards, plug into the bus on the motherboard inside the computer case. The most common bus is PCI Express. See
PCI Express and
PC data buses.
USB - External Peripherals
The most widely used hardware interface for attaching external devices to computers is USB. It connects keyboards, mice, printers, cameras, music players, flash drives and external storage drives. In addition, SATA is a common storage drive and optical drive interface, and NVMe is an increasingly popular SSD interface. The GPIB IEEE 488 standard is used for process control instruments. See
USB,
SATA,
NVMe,
GPIB and
plugs and sockets.
Networks
The de facto standard for connecting devices to local networks (LANs) is Ethernet, which is also used to hook up a cable or DSL modem. The standards for wireless are Wi-Fi and Bluetooth. See
Ethernet,
Wi-Fi,
Bluetooth and
standards.