What Is a TOSLINK Audio Connection?

Learn how digital optical outputs send audio from one component to another

More commonly known as an optical, digital optical, or fiber-optic audio connection, the TOSLINK connection system (both port and cable) was originally developed by Toshiba. With TOSLINK, electric audio signals are converted to light and transmitted through a fiber made of plastic, glass, or silica.

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

The use of a TOSLINK cable for sending digital audio streams between components is an alternative to HDMI or coaxial connections.

What Systems Use TOSLINK?

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 Pros and Cons

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.

  • Which is better, TOSLINK, digital coaxial, or HDMI?

    HDMI has become the preferred connection standard for most devices since it supports both audio and video signals. For audio, digital coaxial slightly beats out TOSLINK in terms of bandwidth, allowing for higher-quality audio signals.

  • What is mini-TOSLINK?

    Mini-TOSLINK serves the same purpose as TOSLINK, but the connectors are smaller and more closely resemble a standard 3.5mm jack. There are mini-TOSLINK adapters if you need to plug a TOSLINK cable into a mini-TOSLINK port.

  • Is TOSLINK the same as S/PDIF?

    TOSLINK is a type of S/PDIF (Sony/Philips Digital Interface) connector. Both standards rely on the same technology, but there are other types of S/PDIF that support coaxial cables as well as fiber optic.

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