TOSLINK as cheap fiber communication?

[technix]

Do you guys consider TOSLINK hardware a viable way of hobby-grade fiber telecommunication? I have tried it and it worked with reasonable enough effectiveness.

I have even designed a simple 5-pin, nondirectional card edge connector as my "low speed optical module standard" that carries a UART up to 16MHz using a pair of fiber with TOSLINK connectors, in the same vein as SPF or SPF+ modules.

[fcb]

Why? What are you trying to achieve??

TOSLINK (which is POF - plastic optical fibre) will transmit a reasonable amount of data (10+Mbits) over a fairly short distance  (a few M). If you want to go further then you'll have to move over to glass fibre, which is cheaper per M (although the tx/rx are more expensive than POF types, and you'll have to pay for terminations.

I've used IFO parts from LasIRvis.co.uk before if you need an alternative to TOSLINK for POF.

[linux-works]

its acceptable for hobby use.  the connectors are cheap, the isolation is good, data rate is good enough and in the end, its still just ttl signaling on a serial interconnect.

add 2 of them for bidirectional use (2 paths).

[technix]

Why? What are you trying to achieve??

TOSLINK (which is POF - plastic optical fibre) will transmit a reasonable amount of data (10+Mbits) over a fairly short distance  (a few M). If you want to go further then you'll have to move over to glass fibre, which is cheaper per M (although the tx/rx are more expensive than POF types, and you'll have to pay for terminations.

I've used IFO parts from LasIRvis.co.uk before if you need an alternative to TOSLINK for POF.

The problem is that at least in China glass fiber and related equipment are too expensive for me. If situation calls for it I am going to inspect using glass-core multimode LC fiber for such low speed control (and using the same 5-pin electrical interface)

[NiHaoMike]

The receivers are AC coupled and don't like long run lengths.

[tszaboo]

The receivers are AC coupled and don't like long run lengths.

Not according to this:
http://media.digikey.com/pdf/Data%20Sheets/Toshiba%20PDFs/Fiber-Optic%20Devices%20TOSLINK.pdf

I think it is the ACT (gain control) which makes it look like AC coupling.
You can NRZI or manchester code the signal, if you have to transmit DC. Although, I'm still waiting for someone to release a MHZ class cheap SERDES ASIC.

[technix]

The receivers are AC coupled and don't like long run lengths.

Not according to this:
http://media.digikey.com/pdf/Data%20Sheets/Toshiba%20PDFs/Fiber-Optic%20Devices%20TOSLINK.pdf

I think it is the ACT (gain control) which makes it look like AC coupling.
You can NRZI or manchester code the signal, if you have to transmit DC. Although, I'm still waiting for someone to release a MHZ class cheap SERDES ASIC.

My TOSLINK-based module transmits 9600-115200 baud UART directly perfectly fine. Maybe I can tru drive it faster even, up to a few Mbaud.

Also I think 74AC class can work up to 100MHz, and my experiences with small MAX II CPLDs (like EPM240T100C5N) told me that those can be programmed into a 75MHz SerDes.

[Marco]

TOSLINK cables are POF, but really shitty POF. Avago says they can do fast ethernet over 70m NA0.3 POF with their transceiver.

GI-POF can do a lot better than that of course, but I don't know if you can buy COTS transceivers for that. At that point alignment probably becomes just as big a headache as with glass fiber, but bits of fiber not having the ability to outright murder you is nice.

[technix]

TOSLINK cables are POF, but really shitty POF. Avago says they can do fast ethernet over 70m NA0.3 POF with their transceiver.

GI-POF can do a lot better than that of course, but I don't know if you can buy COTS transceivers for that. At that point alignment probably becomes just as big a headache as with glass fiber, but bits of fiber not having the ability to outright murder you is nice.

My TOSLINK POF transceiver modules costs me 3 bucks to make and I will sell them for 5 bucks each, and for two bucks I can get a pair of 10 meters long fiber that works with reasonable performance. Good enough, I think.

[madires]

TOSLINK is fine for low speed applications, i.e. up to 25 Mbit/s or so. For higher data rates you should use multimode OM3 or OM4, which are standard for short range (roughly 500m) network (Ethernet) and optical transport (SDH) applications.