Many devices can be connected to and used with a computer. Hardware devices connected to a computer are commonly known as peripheral devices. These devices serve specific purposes, enhance a computer's functions, or add a new service or resource. Peripheral devices include both input and output devices.

The following are examples of peripheral devices:

• Optical drive: A peripheral device that uses an optical storage medium such as CD, DVD, and Blu-ray discs to access data, including text, audio, video, and graphics.

• Speakers: A device that enables users to hear sound.

• Modem: An electronic device that converts the digital signals produced by a computer into specific frequencies for travel over telephone or cable television lines.

• External drive unit: A peripheral device (such as a Hard Drive) attached to the system unit, and used for storing data.

• iPod: A portable digital media player created by Apple that is an external data storage device. The iPod stores songs, movies, games, audiobooks, and photos.

• Biometric Scanners: Technology with ability to recognize individuals via a physical trait (face recognition, fingerprint, iris recognition, hand geometry). It is typically used for authentication and/or security purposes.

• Webcam: Most commonly used for video telephony, a webcam is connected to a computer via a USB port or via an Ethernet or Wi-Fi network. It is used to capture video images in real time or to record video files. Webcams can be used with a variety of software programs and applications.

• Microphone: A device that changes sound energy into electrical signals. A microphone is used to input sounds into a computer.

• Joystick: An input device used to control on-screen movement. Usually, a joystick is used in game applications to control the movement of some object, such as an animated character.

• Flash memory card reader: Data storage device used mostly with digital cameras, mobile phones, video game consoles, and mobile computers.