Electronics > Projects, Designs, and Technical Stuff
Plastic vs glass fiber TOSLINK?
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tooki:
Yep. Heck, TOSLINK syncs even once the cable is halfway into the connector, it doesn’t even have to be seated properly. It’s very forgiving.

I’m actually kinda surprised we don’t use more low-cost optical fiber links using the same technology. Surely plastic optical fiber is cheaper than copper? And in some applications, it’d help eliminate ground loops that mess up audio recording. (I could imagine USB being done optically, for example.)

The only real downside is that it doesn’t carry power, but one could bond it to copper cable for that, perhaps even integrated into a single connector. That and minimum bend radiuses, though again it tends to be rather forgiving, and one could probably make it much thinner, to make the bend radius smaller.
LapTop006:

--- Quote from: tooki on April 01, 2019, 09:31:47 am ---I’m actually kinda surprised we don’t use more low-cost optical fiber links using the same technology. Surely plastic optical fiber is cheaper than copper? And in some applications, it’d help eliminate ground loops that mess up audio recording. (I could imagine USB being done optically, for example.)

The only real downside is that it doesn’t carry power, but one could bond it to copper cable for that, perhaps even integrated into a single connector. That and minimum bend radiuses, though again it tends to be rather forgiving, and one could probably make it much thinner, to make the bend radius smaller.

--- End quote ---

Corning do some USB optical cables although they integrate the transceivers.
Richard Crowley:
At 3m (10ft) attenuation is NOT an issue.  TOSLINK was designed to be used with very inexpensve extruded plastic "cable".
Of course, as with ANY basically simple concept there are snake-oil shysters who will sell you something at 10x or 100x or 10000x the price with the completely baseless claim that it is "better".

The whole issue of "jitter" appears to be a relic of the early days of very simple consumer digital audio.  No modern digital audio uses the raw derived clock from the digital stream.  All modern consumer gear (and all modern commerical/broadcast, etc. gear uses local, crystal-referenced re-synchronization. 

Yes you will find audiophools even here in EEVblog Forum who defend the baloney. As with all audiophoolish concepts, we have never seen any objective proof of the myth.  Note that even the longest optical fiber connections (undersea cables) are thousands of miles/kilometers long in the harshest of conditions with very few booster/repeater amplifiers.  You could count the number on one hand.  Surely if "jitter" were a problem, you would not be able to read this message (or any of the other billions on the internet. 

Essentially, ALL of the "internet" is connected through undersea optical fiber.  Satellite communication has horrible latency because of the altitude of the geosynchronous Earth orbit. (around 500ms full duplex).  Anyone who has done live television via satellite knows that you must keep an offset program clock that is ~500ms ahead in order to hit your time slot properly.  (Been there, done that, have the T-shirt) You can see this every day on international news broadcasts where it takes an uncomfortably long time between when the local news-reader (in America "anchor") asks a question of the reporter out in the field on the other side of the planet replies.  You are seeing the combined latency in both directions.

Certainly, there are glass-fiber TOSLINK cables (and connector adapters from TOSLINK to proper glass-fiber).  They are commonly found in commercal operations where they use already-existing fiber cables, and/or where they are in large plants where they have to send the signal over distances too long to be reliably sent via dirt-cheap extruded plastic "cable".  But that is because of attenuation in the plastic waveguide and has nothing to do with "jitter".  If we can see absolutely flawless video which has been encoded into digital, send thousands of kilometers and reproduced on your TV screen (or smart-phone) with zero artifacts, why do we still believe in the myth of digital "jitter"?   :bullshit:
Berni:
The same people have also made a optical Thunderbolt cable quite a while ago.

I seen it in a linus tech tips video where to prove a point they ran the cable from a computer to the next house where they had a thunderbolt hub to run a monitor and USB devices, all at full speed. Pretty impressive stuff.
Richard Crowley:

--- Quote from: Berni on April 01, 2019, 11:44:48 am ---The same people have also made a optical Thunderbolt cable quite a while ago.
--- End quote ---
Thunderbolt was originally conceived for optical interconnection.
In modern practice most shorter, less expensive Thunderbolt cables are copper because it is cheaper for short distances.

Ref: https://en.wikipedia.org/wiki/Thunderbolt_(interface)#Copper_vs._optical
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