Audio encompasses a large number of interfaces including digital and analog. These are used in a number of applications from home theater and portable use to the pro audio mixing boards that DJ’s and other audio professionals use. One similarity that most audio connector types share is they are easy to connect. Manufacturers of consumer electronics prefer to use simple interfaces that average users can connect and disconnect without having to tighten thumbscrews, or release tabs or latches. This preference can prove challenging to manufacturers who must balance convenience with performance.
¼-inch (6.3mm) and ¼-inch TRS
Often used in pro-audio applications, this connector is also known as a phone connector. This is because it was used for years by telephone operators to patch telephone connections together. It has a tip/ring/sleeve design, like the 3.5mm connector, but it is larger in length and diameter. The 1/4-inch connectors may have only a tip and sleeve, or a tip, ring and sleeve (TRS). A TRS connection is used for balanced audio lines, or depending upon the equipment, for stereo sound. The 1/4-inch connectors are very common on musical instruments (especially guitars), and other staging devices such as effects pedals, mixing consoles, speakers, and amplifiers.
The 3.5 mm connector is commonly called a 1/8-inch connector or a mini-plug. This connector is a small, thin metal plug that can be used to carry one, two, or even three signals. The tip of the plug is separated from the sleeve of the connector by a concentric band of insulating material. For stereo or audio/video versions of the plug, there may be one or two additional metal bands, called rings, placed between the tip and the sleeve.
3.5mm Optical Mini Plug
Similar in size to the standard 3.5 mm connector, the 3.5 mm Optical Mini Plug is designed for digital audio application. This connector is commonly found on Apple computers and some portable audio devices.
Banana plugs are often used to make speaker wire connections on amplifiers, speakers, and audio wall plates. A banana plug has a metal pin that “bows” out in the middle, resembling the shape of a banana. Banana plugs are normally used in pairs and mate with binding posts, which are typically found on higher-end amps and speakers.