TOSLINK
TOSLINK is a standardized optical fiber connector system. Generically known as optical audio, the most common use of the TOSLINK optical fiber connector is in consumer audio equipment in which the digital optical socket carries a stream of digital audio signals from audio equipment to an AV receiver that can decode two channels of uncompressed, pulse-code modulated audio; or decode compressed 5.1 or 7.1 surround sound audio signals, such as Dolby Digital and DTS. Unlike an HDMI connector cable, a TOSLINK optical fiber connector does not possess the bandwidth capacity to carry the uncompressed audio signals of Dolby TrueHD and of DTS-HD Master Audio, but it can carry up to 8 channels of PCM audio when used to connect two devices that use the ADAT Lightpipe standard.
Although the TOSLINK connector supports several media formats and physical standards, the most common digital audio connectors are the rectangular EIAJ/JEITA RC-5720. In a TOSLINK connector, the optical signal appears as a red light, with a peak wavelength of Depending on the type of modulated signal being carried, other optical wavelengths can be present.
History
Toshiba originally created TOSLINK to connect their CD players to the receivers they manufactured, for PCM audio streams. The data-link layer is based on the Sony/Philips Digital Interface, while the hardware layer utilizes a fiber optic transmission system, rather than the electrical hardware layer of S/PDIF. TOSLINK was soon adopted by manufacturers of most CD players. It can often be found on video source to connect the digital audio stream to Dolby Digital/DTS decoders.Although the generic name for the connector is the EIAJ optical, the trade name TOSLINK is a registered trademark of the Toshiba electronics company, derived from TOShiba-LINK; other etymologic variations were the words TOSlink, TosLink, and Tos-link.
The ADAT Lightpipe uses an optical transmission system similar to that of the TOSLINK connector used in the professional recording of music and in the audio component industry. The ADAT Lightpipe connector format uses the same JIS F05 connectors as the TOSLINK connector, the ADAT Lightpipe data format is incompatible with S/PDIF.
Properties and problems
Due to their high attenuation of light, the effective range of plastic optical cables is limited to. They can temporarily fail or be permanently damaged if tightly bent. Although less commonly available and more expensive than plastic optical fiber cables, glass or silica optical fibers have lower losses and can extend the range of the TOSLINK system.Optical cables have galvanic isolation, thus are not susceptible to electrical problems such as ground loops, RF interference, ESD events.
Design
[Image:Fiber optic illuminated.jpg|thumb|left|A TOSLINK fiber optic audio cable being illuminated by a laser on the left end]Several types of fiber can be used for TOSLINK: inexpensive plastic optical fiber, higher-quality multistrand plastic optical fibers, or quartz glass optical fibers, depending on the desired bandwidth and application. TOSLINK cables are usually limited to in length, with a technical maximum of, for reliable transmission without the use of a signal booster or a repeater. However, it is very common for interfaces on newer consumer electronics to easily run over on even low-cost TOSLINK cables. TOSLINK transmitters operate at a nominal optical wavelength of.