It is one of several methods for transmitting digital audio signals between components in consumer audio systems.

If you take a look at the fiber optic end of a connected TOSLINK cable, you’ll notice a red dot beaming light back at you. The cable end is flat on one side and rounded on the other, so there’s only one orientation for plugging it in. Many wireless audio adapters, HDTVs, home theater equipment, DVD/CD players, receivers, amplifiers, stereo speakers, computer sound cards, and video game consoles feature this type of digital optical connection. Sometimes it can be found paired alongside video-only connection types, such as DVI or S-video.

TOSLINK cables are designed to handle lossless stereo audio and multi-channel surround sound, such as DTS 5.1 or Dolby Digital. The benefits of using this kind of digital connection are immunity to electromagnetic noise interference and great resistance to the loss of signal over the distance of the cable (most notably with higher-quality cables). However, TOSLINK isn’t without a few drawbacks. Unlike HDMI, this optical connection is unable to support the bandwidth required for high-definition, lossless audio (for example, DTS-HD or Dolby TrueHD)—at least not without compressing the data first. Also unlike HDMI, which proves its versatility by carrying video information in addition to audio, TOSLINK is audio-only. The effective range (the total length) of TOSLINK cables is limited by the material type. Cables with optic fibers made of plastic are often no longer than 5 m (16 ft), with a maximum of 10 m (33 ft). You need a signal booster or repeater with additional cables to span greater distances. Glass and silica cables can be manufactured to longer lengths, due to the improved performance (less data loss) of transmitting audio signals. However, glass and silica cables tend to be less common and more expensive than their plastic counterparts. And all optic cables are considered fragile, being that any portion can be damaged if bent or coiled too sharply.