Digital Optical Connection - What It Is And How To Use It

Digital Optical (Toslink) Connection
Digital Optical (Toslink) Connection. Photo © Robert Silva - Licensed to About.com

Definition of a Digital Optical Connection

A digital optical connection is a type of connection that uses light (fiber optics) to transfer audio data digitally from a compatible source device to a compatible playback device. The audio data is converted from electrical pulses to light pulses on the transmission end, and then back to sound pulses on the receiving end.

Contrary to popular belief, the light is not generated by a laser - but is generated by a small LED light source on the transmission end, which can be sent through the fiber optical cable to a compatible connection on the receiving end.

Digital Optical Connection Applications

In home audio and home theater, Digital Optical connections are used for transferring specific types of digital audio signals.

Devices that may provide this connection option include DVD players, Blu-ray Disc players, Media Streamers, Cable/Satellite Boxes, Home Theater Receivers, and, in some cases CD players and newer Stereo Receivers.

The types of digital audio signals that can be transferred by a Digital Optical Connection include: two-channel stereo PCM, Dolby Digital, Dolby Digital EX, DTS Digital Surround, and DTS ES.

It is important to note that digital audio signals, such a 5.1/7.1 channel PCM, Dolby Digital Plus, Dolby TrueHD, Dolby Atmos, DTS-HD Master Audio, and DTS:X cannot be transferred via Digital Optical connections - These formats require HDMI connections.

The reason for this difference is that when the Digital Optical connections was developed, it was made to comply with digital audio standards at the time, which did not include 5.1/7.1 channel PCM, Dolby Digital Plus, Dolby TrueHD, Dolby Atmos, DTS-HD Master Audio, or DTS:X .

In other words, Digital Optical cables do not have the bandwidth capability to handle some newer home theater surround sound formats.

It is also important to point out that, as of 2015, although all Home Theater Receivers, DVD player, most Media Streamers, Cable/Satellite Boxes, and even some Stereo Receivers have a Digital Optical connection option, there are some Blu-ray Disc players that eliminated Digital Optical connection as one of the audio connection options, opting for an HDMI output-only connection for both audio and video.

In other words, if you have a home theater receiver that has the Digital Optical connection option, but does not provide the HDMI connection option, make sure that when you are shopping for a newer Blu-ray Disc player, that it does, indeed offer, a Digital Optical connection option for audio.

NOTE: Digital Optical Connections are also referred to as TOSLINK (which is short for Toshiba Link). connections.

For more on the history, construction, and more detailed specifications of Digital Optical/Toslink connections, refer to TOSLINK Interconnect History & Basics (Audioholics).

More Info

For an additional look and explanation, also watch our About.com Video Presentation: What is a Digital Optical Cable?

Also, there is another digital audio connection that is available that has the same specifications as Digital Optical, and that is Digital Coaxial, which transfers digital audio signals over tranditional wire, rather than light. For more on this connection, including a photo, refer to my article: Digital Coaxial Connection - Definition and Explanation.

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