Headphones

Sometimes referred to as earphones, headphones are a hardware output device that either plug into a computer line out or speakers. Headphones allow you to listen to audio or watch a movie without disturbing people around you. The picture is an example of a USB headset from Logitech, which also include a microphone (an input device), a popular solution for computer gaming.

The first pair of audio headphones were invented by Nathaniel Baldwin in 1910. The U.S. Navy ordered 100 pairs them because they recognized the potential advantages, despite many people being skeptical about their usefulness.

Headphones come in several shapes and styles. The traditional style looks similar to those shown above. Headphones utilize styrofoam or another soft fabric around the earpieces to provide a comfortable fit around your ear and a plastic or light metal band between each earpiece.

The most basic type of headphones, earbuds, are small and fit inside your ear. They are usually shaped in a specific way to be as comfortable as possible. Some earbuds come with several sets of different rubber inserts. Depending on the size of the user's ears, they can choose the size of rubber insert that best fits their ear canal.

Line out

Alternatively referred to as audio out and sound out, the line out jack is found on computer sound cards. It allows external speakers, headphones, or other output devices to be connected to the computer, transfering computer generated audio to the devices so that it can be heard.

The picture shows a green line out port represented as an arrow pointing out of sound waves on the back of a desktop computer sound card. For laptops, smartphones, tablets, and other devices the line out is the only hole big enough for a Mini Plug cable.

Jack

A jack is similar to a port and is a hole or other connection that allows a compatible plug to connect into the jack. You always plug something into a jack and is most often used when describing an audio jack.

Examples of audio jacks

·         Microphone jack

·         Sound in and Line in

·         Sound out and Line out