TOSLINK

TOSLINK is a brand name for an optical fiber-based interface used to transmit digital audio data. Developed by Toshiba in the 1980s, its purpose is to provide an electrical-noise-free connection between consumer audio and video equipment by sending data as light through an optical fiber rather than as electrical signals. The interface is commonly used to carry the S/PDIF protocol, making it the optical variant of a consumer digital audio connection.

The physical layer uses an infrared light source (typically around 650 nanometers) and a photodetector. The data are framed according to the S/PDIF standard, allowing stereo PCM audio and multichannel compressed formats such as Dolby Digital or DTS, depending on the devices. In practice, TOSLINK transmits the same data stream as other S/PDIF implementations, but over optical fiber rather than coaxial or electrical cables.

Physical connectors come in two common forms: the full-size TOSLINK connector, which is the square optical plug, and the mini-TOSLINK connector (a 3.5 mm optical jack) used on some laptops and portable devices. Cables are typically made from plastic optical fiber and can run for several meters; longer runs require careful cable choice to maintain signal integrity.

Advantages of TOSLINK include immunity to electromagnetic interference and the avoidance of ground loops. Disadvantages include the fragility of optical cables and potential compatibility issues with devices that lack optical inputs or that require specific formats. TOSLINK remains widely used in home theater systems, audio interfaces, and various consumer electronics for digital audio connections.