What Is an Optical Digital Cable?

by Joe Fletcher

When it comes to home theater, there are several types of cable that can be used to connect your components with your receiver. Two of the traditional options are optical cable and digital coax, while a more recent standard is HDMI. Optical jacks are included on many types of equipment and are a good method of connection.


Optical digital cable is a fiber cable that uses light pulses to transmit a digital audio signal. Unlike other audio cables including RCA and digital coax, which use the more traditional method of electrical signals sent via conductive wire, optical cable uses on/off pulses of light. Many times optical cable will be denoted as TOSLINK, which stands for Toshiba Link, indicating its introduction by Toshiba. The more generic label for the standard optical interface is EIAJ.


Digital cable is necessary to carry digital audio signals that are used for surround sound formats. Optical is one of the options and is generally considered slightly superior to the other main option of digital coax.


When connecting two components via optical cable, ascertain that each component has an optical jack. To connect simply, pull out the plastic tab from each jack and plug the cable into the jack. You will notice a beam of red light emitting when the tab is pulled out. This red LED light will transmit the audio signal.


Fiber optic cables are composed of a core and an outer layer called a cladding. The refractive index of the core is higher than the index of the cladding and, when light is introduced, the light will be reflected at an angle off the top and bottom of the core and will travel down the wire, carrying the information that is contained within the signal.

Other Uses

In addition to home theater and audio, digital optical cables are used for other applications including car audio and navigation, and factory and office automation.

Pros and Cons

Optical cable is not subject to electrical and radio interference the way copper wire is. However, optical cable can be hampered by significant bends in the cable, around corners for instance, given its reliance upon light.

About the Author

Joe Fletcher has been a writer since 2002, starting his career in politics and legislation. He has written travel and outdoor recreation articles for a variety of print and online publications, including "Rocky Mountain Magazine" and "Bomb Snow." He received a Bachelor of Arts in political science from Rutgers College.

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