Computer Hardware Terminology and Definitions

Term

Definition

Hardware

The physical components that compose a computer system or network. Common hardware components include the following:

• Keyboard, mouse, monitor, printer
• Connectors and cables
• Hard disk drives
• Circuit boards

Software

Software components include the following:

• Operating systems.
• Program applications.
• Hardware drivers (special programs that tell the operating system how to use the hardware.)

Note: Firmware is a special type of software that is embedded in the read-only memory of a hardware component. A BIOS chip is an example of firmware.

Port/Cable

Description

VGA (DE-15)

The video graphics array (VGA) port is used to connect external display devices such as projectors and some monitors. VGA ports:

• Transmit an analog video signal.
• Have three rows of five pins.
• Use a DE-15 connector.

DE-15 connectors are often called DB-15 connectors, which is a misnomer.

DVI

A digital visual interface (DVI) port is used to connect display devices. DVI ports:

• Carry either an analog signal, a digital signal, or both.
• Support one of two cable and connector types, single link or dual link.

HDMI

DisplayPort

The High-Definition Multimedia Interface (HDMI) port and DisplayPort are used to send high-quality digital video and audio signals. The following devices use the HDMI and DisplayPort:

• LCD monitors
• HDTVs

HDMI has a smaller form factor connector called an HDMI-mini connector. This connector is half the size of a standard HDMI connector and is used to connect smart phones, tablets, and digital cameras to external displays.

Thunderbolt

The Thunderbolt port combines PCI Express (PCIe) and DisplayPort signals into a single interface. The Thunderbolt port can also provide DC power. Thunderbolt ports are mainly used for external displays.

S-Video (miniDin-4)

The separated video (s-video) port is used for connecting external displays. It has slightly better picture quality than an RCA video port.

USB

The USB port is one of the most common computer ports. USB ports are used to connect a variety of devices.

• Mouse and keyboard devices
• External storage devices
• Digital cameras
• Printers
• Scanners
• Microphones
• Webcams

Audio Jack

Audio jacks are used to send or receive analog audio signals. Audio jacks use 3.5 mm TRS connectors to connect audio devices such as:

• Speakers
• Headphones
• Microphones
• Audio output devices

Audio jacks use a common color code to denote the port type:

• Green: line out
• Pink: mic in
• Blue: line in
• Orange: subwoofer
• Black: rear speakers

Coaxial S/PDIF

Fiber S/PDIF

The S/PDIF port is used to send a digital audio signal to high-end audio devices such as home theatre systems or Dolby Digital surround sound systems.

• Coaxial S/PDIF ports use a copper coaxial cable to transmit signals.
• Fiber S/PDIF ports use fiber optic cables to transmit signals.

RJ45

RJ45 ports are used to create Ethernet networks by connecting multiple computers and networking devices. RJ45 ports have eight connector pins.

RJ11

RJ11 ports are used by telephones and modems to send analog signals. RJ11 ports have four connector pins.

PS/2 (Mini-DIN-6)

The PS/2 port, also called mini-DIN-6, is used to connect older PS/2 keyboard or mouse devices. PS/2 ports are color coded. Purple denotes the keyboard port, and green denotes the mouse port.

NOTE: The PS/2 port has been superseded by the USB port.

Serial (DB-9)

The serial port is used to connect serial devices, such as a barcode scanner, dial-up modem, or serial mouse. Serial ports are also used to configure and manage some networking devices.

NOTE: RS-232 is a standard for serial communication transmission of data. It defines the signals connecting computer equipment like a computer and a modem. The RS-232 standard was commonly used in computer serial ports. USB has replaced RS-232 for most of its peripheral interface roles. Many computers no longer come equipped with RS-232 ports.

Parallel (DB-25)

The parallel port connects older devices that use a parallel interface, such as printers, hard drives, and gamepads.

NOTE: The parallel port was superseded by the USB and RJ45 port.

DB-15

The DB-15 port is used by legacy gamepads, joysticks, and MIDI devices.

NOTE: These ports are typically found on older sound cards.

Adapter

Description

HDMI to DVI

Used to connect an HDMI cable to a DVI port.

VGA to DVI

Used to connect a VGA cable to a DVI port.

VGA to HDMI

Used to connect a VGA cable to an HDMI port.

Ethernet to USB

Used to connect an RJ45 connector to a USB port.