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Thread: Is a 50' optical cable OK to use? |
    
Gold Member Username: Samijubal
Post Number: 3253
Registered: Jul-04
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| Posted on Friday, January 26, 2007 - 11:40 am: |
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Can I run an optical cable 50' without problems? I know they sell cables in 50' lengths. Has anyone used a cable that long without problems? |
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Platinum Member Username: Project6
Post Number: 12577
Registered: Dec-03
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| Posted on Friday, January 26, 2007 - 12:05 pm: |
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According to BICSI (an organization specializing in telecommunications), the longest practical length of an optical cable is limited to 20 feet. Anything longer than that is susceptible to errors due to internal reflections. |
Gold Member Username: Hawk
Highlands Ranch,
CO
USA
Post Number: 1098
Registered: Dec-03
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| Posted on Friday, January 26, 2007 - 05:13 pm: |
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Berny:
I am not challenging your information, but I find that hard to believe. Fiber optic cable runs for miles without problems. I guess I don't understand why an optical cable would be any different. |
Platinum Member Username: Project6
Post Number: 12581
Registered: Dec-03
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| Posted on Friday, January 26, 2007 - 06:02 pm: |
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No worries, mate. I am quite wary of that myself, but I have not the experience necessary to make the call. I was reading about Toslink limitations and apparently 20 feet is the effective length without any significant data degradation. I do not know if that applies to data stream for telecommunications or if it applies to digital audio as well.
I retrieved the information from bicsi.org |
Silver Member Username: Arande2
400dB could probably d...,
SouthWest Mi...
Too Many DBs...
Post Number: 937
Registered: Dec-06
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| Posted on Friday, January 26, 2007 - 06:46 pm: |
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I think the reason they can carry for miles is that the telephone company uses a balanced system compared to consumer cables. They also use ultra-pure glass. My 2 cents |
Gold Member Username: Samijubal
Post Number: 3254
Registered: Jul-04
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| Posted on Friday, January 26, 2007 - 08:22 pm: |
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Well one place I talked to said what Berny said, about 20-25', another place said they've installed up to 150' without problems. I ordered a 50' cable, so I guess I'll find out. It's either that or use the RG6 analogs I've already got running back there, but we all know the audio difference between analog and digital. |
Gold Member Username: John_s
Columbus,
Ohio
US
Post Number: 1330
Registered: Feb-04
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| Posted on Friday, January 26, 2007 - 11:23 pm: |
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A friend of mine had a custom install that included a 35' Toslink. No probs. |
Gold Member Username: Hawk
Highlands Ranch,
CO
USA
Post Number: 1102
Registered: Dec-03
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| Posted on Saturday, January 27, 2007 - 07:17 pm: |
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Andre:
The glass used in toslink is the same as fiber optic cable. It's all made by companies like Owens-Corning and JDS Uniphase. |
Gold Member Username: Hawk
Highlands Ranch,
CO
USA
Post Number: 1103
Registered: Dec-03
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| Posted on Saturday, January 27, 2007 - 07:28 pm: |
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OK. I did a little research and now I understand the issue.
What length you can use depends upon the type of fiber optic cable used. Apparently, some toslink cables use plastic optical fiber. Thus, the length that may be safely used without signal degradation is as Berny described, about 20-25 ft. However, high quality toslink cables used optical quality glass fiber optical cable, and these may be run at very long lengths without loss of signal quality. Instead, the limiting factor is the strength of the signal light of the transmitter (CD player, DVD player, etc.).
I guess the lesson I have learned is that from now on, whenever I need to buy a toslink cable, I will make sure it has a glass fiber conductor. |
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Bronze Member Username: Usernamex
London
England
Post Number: 48
Registered: Oct-05
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| Posted on Wednesday, January 31, 2007 - 09:25 am: |
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Mostly 'cause I'm cheap, I was wondering if a optical to coaxial converter and a 50ft run of coaxail could be more cost effective? Hmm, researching my own question, nope doesn't look like it. FYI, Blue Jeans cable claim to have tested Mitsubishi's ESKA Fiber plastic optical fibre out to 50 ft. They also noted...
"While POF is in general rather lossy stuff compared to glass optical fiber, we prefer it for optical digital audio use because it's much more physically durable and because its aperture matches the spec for optical digital audio use, unlike glass fiber which is too small and must be used in bundles"
http://www.bluejeanscable.com/store/digital-audio/index.htm |
Gold Member Username: Samijubal
Post Number: 3281
Registered: Jul-04
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| Posted on Thursday, February 01, 2007 - 12:13 am: |
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I got the cable today, ran it to the back room, it works fine. The cable was only $20 + $7.50 shipping from Amazon marketplace. Nice cable, metal ends and 7mm, not the 5mm cables I found most other places. |
Platinum Member Username: Project6
Post Number: 12701
Registered: Dec-03
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| Posted on Thursday, February 01, 2007 - 10:49 am: |
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That's good info for those of us wondering.
Which company made the cable? |
Gold Member Username: Samijubal
Post Number: 3283
Registered: Jul-04
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| Posted on Thursday, February 01, 2007 - 04:17 pm: |
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Acifica.
Here's the Amazon link:
http://www.amazon.com/Gold-Digital-Optical-Toslink-Cable/dp/B000CSWFQC
The only problem is I have to set the delay on the receiver different for the DVD and satellite. I'm guessing there's a delay in the 50' cable since the delay on the receiver has to go higher for the DVD and lower for the sat, which is the 50' cable. On an SDTV without the delay of a digital TV, it might not work, the audio may be behind the video. |
