A hardware interface/ port is a socket on the outside of the system unit that is connected to an expansion board on the inside of the system unit. A Port allows connecting a peripheral device such as a monitor, printer, or modem so that it can communicate with the computer system.

A parallel port allows lines to be connected that will enable 8 bits to be transmitted simultaneously, like cars on an eight-lane highway. Parallel lines move information faster than serial lines do, but they can transmit information efficiently only up to 15 feet. Thus, parallel ports are used principally for faster-speed devices such as connecting printers.

A serial port, or RS-232 port, enables a line to be connected that will send bits one after the other on a single line, like cars on a one-lane highway. Serial lines are used to link slow-speed devices and equipment that is not close by. Serial ports are used principally for communications lines, modems, and mice. They have frequently labeled COM for communications.

Universal Serial Bus (USB) is a serial bus standard to connect devices to a host computer. It was designed to allow many peripherals to be connected using a single standardized interface socket and to improve plug and play capabilities that is by allowing devices to be connected and disconnected without rebooting the computer or turning off the device. Other convenient feature includes providing power to low-consumption devices, eliminating the need for an external power supply allowing many devices to be used without requiring manufacturer-specific device drivers to be installed.

USB is intended to replace many varieties of serial and parallel ports. It can connect computer peripherals such as a mouse, keyboard, PDA, gamepad, joystick, scanner, digital camera, printer, personal media player, flash drive, external hard drive. For many of those devices, USB has become the standard connection method.

The IEEE 1394 interface is a serial bus interface standard for high-speed communication and isochronous real-time data transfer, frequently used by personal computers as well as in digital audio, digital video, and aeronautics applications. It replaced parallel SCSI in many applications, because of lower implementation cost and a simplified, more adaptable cabling system.

The SCSI is pronounced “scuzzy”, and the SCSI port provides an interface for transferring data at high speeds for up to eight SCSI-compatible devices. These devices include external hard disk drives, magnetic-tape backup units, and CD-ROM drives.

Conventional PCI (often shortened to PCI) is a computer bus for attaching hardware devices to a computer. These devices can take either the form of an integrated circuit fitted onto the motherboard itself, called a planar device in the PCI specification, or an expansion card that fits into a socket. The PCI slot is in the PC to connect devices like network cards, sound cards, internal modems.

HDMI refers to High Definition Multimedia Interface. It is a connector and cable capable of transmitting high-quality and high-bandwidth streams of audio and video between devices. The HDMI technology is used with devices such as an HDTV, projector, game consoles, camera, DVD player, or Blu-ray player.

The length of HDMI cables varies significantly. They can run from one foot up to 50 feet, though it’s not recommended that users buy more than a 25-foot cable as it may result in signal degradation or loss.

An expansion slot is a connection or port inside a computer on the motherboard, alternatively known as a bus slot or expansion port. It provides an installation point for a hardware expansion card to be connected. For example, if we want to install a new video card on the computer, we purchase: a video expansion card and install that card into the compatible expansion slot.