I am often called to connect an audio system to a new TV and I’ve found that consumers are confused about “optical cables”. Not surprisingly, since optical cables have nothing to do with optics and instead are about sound. Almost all new TVs have an audio output in the form of an optical connection. If you run an optical cable from your TV to your sound system, it will transmit audio information, including surround sound, and will follow whatever source your TV is tuned to. That means you can plug various sources into the inputs on your TV and can switch between them without changing your audio system input. Soundbars, which are becoming popular as an alternative to the TV speakers or a full blown surround system, usually work with optical cables and in most cases include them in the box.
It’s called optical cable because it uses fibre optics rather than copper wire to transmit data. While this might make a difference on a long run, it doesn’t improve the sound in any way when used in a home system; its real advantage is that it will fit the available connectors. This cable has been around for a long time, originally developed in 1983 by Toshiba. It was originally called a Toslink cable (short for Toshiba link), so you may still see it referred to by that name. The connector is roughly a square shape and will only fit in one way. When there is data being fed through it, the end glows red. Because there is no copper, there is no electromagnetic interference, which may be why it has become the cable of choice for audio transmission among TV manufacturers.