Talk:TOSLINK

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Top link[edit]

Top link to PDF is dead.

Try the cache on Google at http://72.14.207.104/search?q=cache:4aV5wdHtQ9EJ:www.semicon.toshiba.co.jp//eng/prd/opto/doc/pdf/bce0037a.pdf+toshiba+bce0037a.pdf&hl=en&client=safari


I think you will find the Toslink connector type for Digital Audio is actually JEITA RC-5720, not JIS F05. See http://www.toshiba.com/taec/components/ProdLineGuide/toslink.pdf

Jitter[edit]

"One cause of jitter is bandwidth-limiting of the digital signal." This information cannot be found in article [5]. There is a quote from a stereophile audio magazine, but it is not possible to analyse this information to determine if it is reliable. — Preceding unsigned comment added by 84.25.139.125 (talk) 10:22, 30 December 2011 (UTC)

Multi-stranded cable jitter[edit]

"Multi-strand glass fiber TOSLINK cables might cause less jitter than larger diameter, single strand cables." Jitter is introduced by the modulation and demodulation of the signal, not the medium itself. Being a digital media, the light is either perfectly perceived or not. A google on this line returned a (also dubious) article describing an increase of up to 1.7ns of jitter. Knowing earing is humanly possible up to 25KHz, and Nyquist restrict the signal pertinence to 50KHz, then a 1/1.7ns = 588MHz jitter can be ruled as inaudible. I vote to remove this extremely dubious line. — Preceding unsigned comment added by 74.15.180.166 (talk) 20:14, 14 February 2013 (UTC)

mini Toslink[edit]

Many new laptops now have a combination Headphone/Toslink output. The connector looks like a mini stereo jack except the tip has a fiber connection. You can see an image of the connector at the bottom of the webpage. Fujitsu Siemens calls this output the Spdif out. If the output is enabled in software you can see a red light inside the Jack socket when adjusting the baudrate or for a short period when removing a normal analogue jack from the socket.

Length limit[edit]

The article states "TOSLINK Signal cables are unlimited in length as light does not degrade over length." Is this completely true? I don't know anything about TOSLINK but I know that optical Ethernet cable have a maximum length. Mind you, that is probably more down to timing as Ethernet is a two-way protocol, and after a certain time the other end will give up waiting and the link will go down. Is the same true for TOSLINK? Furthermore, the info box says the length is limited to 10m? Can someone who is knowledgeable about the subject make the article consistent? Pelago 09:34, 5 June 2007 (UTC)

Your argument doesn't seem to be unfounded. The article states (now at 1/15/08) that the maximum length is at 10m before degradation occurs. Is there a source for this information or is it being assumed? Light is light, which travels at (gasp!) the speed of light. That means there technically shouldn't be a maximum length for FI-Ethernet either, considering that these things are traveling at C. (or just under). Unless a server or client is expecting a connection to occur at thousandths of a millisecond, I highly doubt a connection will timeout. Someone needs to contact an proper engineer about this stuff.71.238.205.137 (talk) 05:57, 15 January 2008 (UTC)
The signal does degrade, the plastic optical fiber isn't a perfect transmission medium for light, as it bounces along the fiber (it doesn't travel straight along it as you seem to assume, fibers work by total internal reflection) some of the light will be absorbed by the plastic instead of reflected, and distortions will be introduced into the signal. Because it is used only for digital signals this doesn't matter at all over short distances, but as the distance increases the distortion will eventually exceed the amount which is tolerated by the receiver apparatus and the connection will not function. When using optical fiber for Ethernet rather than audio, there are different grades of fiber used and more or less sophisticated transmitters and receivers depending on the distance. Within a building relatively expensive and fragile glass fiber is used with simple electronics, a cheaper grade of glass fiber is used in conjunction with more expensive electronics for medium distances (e.g. across a city rather than between two buildings on a campus), and for extremely long distances (e.g. transatlantic) it is usual to both use exceptional quality fiber and amplify the signal at intervals using very expensive optical amplifiers. No doubt TOSLINK could be made reliable over considerable distances if it used more expensive electronics and/or fragile glass fiber cables, but that would sort of defeat the convenience and low cost aspects... 82.69.171.94 (talk) 12:18, 16 February 2008 (UTC)
There is no definitive answer to how long can a piece of optical fibre be for digital transmission. It is also not particularly helpful to think of a digital signal being distorted in the way that an analog signal can be. The actual answer depends on the frequency (pulse rate) of the signal. If the pulse rate is too high for the length of fiber then transmission errors will occur because of internal reflection blurring the pulse edges. Therefore any limit set on a fiber's length should take into account the bitrate being used. 84.9.50.233 (talk) 16:16, 24 August 2008 (UTC)

"The speed of light" is only in a vacuum. Light travels slower through plastic, just like electrical signals travel slower through coax (typically around 2/3 the speed of light). This is irrelevant to SPDIF, though, which is unidirectional. There's no issue of timing because the receiver never talks back to the sender. If it takes 5 hours to get to the destination, the audio will just be output 5 hours later than it was sent. What's relevant is the decrease in light intensity over longer cables or bent cables, and the smearing of the edges due to internal reflection.

"Because it is used only for digital signals this doesn't matter at all over short distances, but as the distance increases the distortion will eventually exceed the amount which is tolerated by the receiver apparatus and the connection will not function."

That would be true if it were just digital signals being sent around to digital inputs, but this uses clock recovery. The receiver in this case uses the signal to generate its own sampling clock, so smearing of the transitions can affect the timing used in reconstructing the output signal, but it's not audible in typical equipment. —Preceding unsigned comment added by 96.224.68.51 (talk) 02:09, 25 August 2010 (UTC)

Here's a good article about TOSLINK cables and the difference between cheap cables and good ones. http://www.audioholics.com/education/cables/toslink-interconnect-history-basics Bizzybody (talk) 08:14, 23 December 2010 (UTC)

Light[edit]

What kind of light does it use? 98.222.134.223 (talk) 17:37, 11 October 2009 (UTC)

Red LED. It's not using LASER technology. Since TOSLINK originated in 1983, it would have been far too expensive to use diode lasers for the digital optical outputs. Would be cool to be able to use a computer or other device with TOSLINK as a very awkward laser pointer... ;) Bizzybody (talk) 08:13, 23 December 2010 (UTC)

Citation Needed[edit]

There is a citation needed for this claim: "However, the actual effect of jitter on audio reproduction is an increase in noise or intermodulation, and most humans' hearing is not likely to notice any effect." I have added a citation needed tag to it. 72.197.38.228 (talk) 03:48, 30 December 2013 (UTC)