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Wireless Networks Thread, fiber issues in Technical; I have some cisco convertors (gbic) and a mini gbic convertor i brought off ebay and an orange SC to ...
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    mjs_mjs's Avatar
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    fiber issues

    I have some cisco convertors (gbic) and a mini gbic convertor i brought off ebay and an orange SC to LC fiber patch. when i connect them up it doesn't work. What am i missing?

    I have tried swapping the cores over at one end incase it was miss fibered, but nothing.

    Going from a linksys slm2024, to a 3com superstack3.

    thanks

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    jamesreedersmith's Avatar
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    Could be one end is configured for single mode and the other is configured for multimode.

    Thanks

    James

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    DMcCoy's Avatar
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    What category are the fibres?

    62.5 or 50nm? The fibre and patch leads should say. What speed is each end, and what type are the convertors sx, lx etc?

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    mjs_mjs's Avatar
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    Quote Originally Posted by jamesreedersmith View Post
    Could be one end is configured for single mode and the other is configured for multimode.

    Thanks

    James
    Quote Originally Posted by DMcCoy View Post
    What category are the fibres?

    62.5 or 50nm? The fibre and patch leads should say. What speed is each end, and what type are the convertors sx, lx etc?
    the cisco convertor end, 1000base-lx 1300nm laser, 21cfr(j) class 1
    the other enda finisar ftrj-8519-3-2.5 850nm, 21 cfr(j) class 1

    cable says; optical cable - 62.5/125 fiber ofnr (ul) c (ul) 00878 feet 807006

    i'm guessing that the 1300nm and 850nm mean i have incompatable FO transeivers/convertors?

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    DMcCoy's Avatar
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    1300nm is single mode, 850nm is multimode, you need them to be the same.

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    mjs_mjs (9th November 2009)

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    mjs_mjs's Avatar
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    Quote Originally Posted by DMcCoy View Post
    1300nm is single mode, 850nm is multimode, you need them to be the same.
    Which is better and can my fiber handle both? i've herd that orange fibers, like this one, are multimode and yellow ones are single mode. Is that correct?

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    plexer's Avatar
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    What is the fibre between the 2 that you are trying to connect to is it multimode or singlemode fibre you need to look behind the fibre patch panels and see what's written on it.

    Ben

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    The cisco gbic is LX while the Finisar is SX. They're not compatible with each other. It's nothing to do with propagation mode.

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    mjs_mjs's Avatar
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    Quote Originally Posted by plexer View Post
    What is the fibre between the 2 that you are trying to connect to is it multimode or singlemode fibre you need to look behind the fibre patch panels and see what's written on it.

    Ben
    trying to go switch to switch atm so only down an orange fiber.

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    mjs_mjs's Avatar
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    Quote Originally Posted by keithu View Post
    The cisco gbic is LX while the Finisar is SX. They're not compatible with each other. It's nothing to do with propagation mode.
    I'm not sure i understand this. What is LX/SX?.

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    john's Avatar
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    Quote Originally Posted by mjs_mjs View Post
    I'm not sure i understand this. What is LX/SX?.
    S is Short Wave Length
    L is Long Wave Length when used in this terminology, often the S is the cheaper part and uses LEDs rather than Lasers to transmit data. Its used surprisingly enough over shorter distances than the L.

    To help more what is the type of fibre between the two panels, the Jacket colour makes no difference, If you go that way I've got Black fibre on my place and I know that its 62.5/125 OM1 Fibre (I know as I ordered and fitted it), but I've also got Blue jacket and Orange jacket at that same type.

    It will be stamped on the jacket somewhere on it so have a read around the jacket and confirm.

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    mjs_mjs (10th November 2009)

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    Quote Originally Posted by mjs_mjs View Post
    I'm not sure i understand this. What is LX/SX?.
    There are two standards of optical transceivers in common use on LANs: SX and LX.
    SX transceivers (gbics) use Short wavelength light with a wavelength of 850nm.
    LX transceivers (gbics) use Long(er) wavelength light with a wavelength of 1300nm.

    Each type can only send and receive its own specific wavelength of light, so if you connect dissimilar ones together they won't be able to talk to each other. This is your problem.

    The patchlead you have is almost certainly multi-mode. This refers to the way the light is constrained as it passes through the core of the fibre, which typically has a diameter of 62.5um (micro-metres) or 50um. The diameter will be printed on the jacket somewhere if you look closely. The fact that it's orange is irrelevant - you can get them in lots of colours. Multi-mode fibres can be used with both SX and LX gbics.

    To send the signal over long distances single-mode fibres are used. These typically have a core diameter of 9um and are used with LX gbics only. These fibres and gbics are much more expensive.

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    mjs_mjs (10th November 2009)

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    mjs_mjs's Avatar
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    can you change from single mode cable to multimode and back again?

    we have LX convertor to yellow cable (9/125) then apparently over multimode fiber (unknown fiber) back to yellow cable (9/125) then another of the LX convertors.

    It works and has been flawlessly for 7 years now, my quesion is, is it right?

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    SYNACK's Avatar
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    Quote Originally Posted by mjs_mjs View Post
    can you change from single mode cable to multimode and back again?

    we have LX convertor to yellow cable (9/125) then apparently over multimode fiber (unknown fiber) back to yellow cable (9/125) then another of the LX convertors.

    It works and has been flawlessly for 7 years now, my quesion is, is it right?
    If it works then it is probably right and you probably have 9/125 the whole way through. Swapping between cable types causes huge signal loss and you would probably have noticed the link performing really badly and dropping lots of packets.

    You should be able to check if you can find an exposed bit of the shethed fiber either by looking behind the rack or pulling off some wall capping that it travels through and checking the lableing as it is printed usually every one to three meters on the outside of the fibre.

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