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I have a 1500' fiber run to make for data 10/100. The interface on each end is multi-mode, but the cable I have is single mode. Can this be done? I'm new to fiber so be gentle with me.

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    With rare exceptions, you can't mix multimode and single mode cable/optics.
    – Ron Trunk
    May 16 '15 at 16:09
  • Can please be clearer? Is your 1.5 KM run multimode fiber or is it a 1.5KM single-mode fiber run?
    – user4565
    May 16 '15 at 20:25
  • the fiber is single mode and the interface on each end is multimode.
    – doyle
    May 21 '15 at 12:59
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    Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Aug 11 '17 at 16:57
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The scenario you are asking about will not work.

The answer is in the name - "multimode" fibre carries multiple modes of light. "Singlemode" fibre carries only a single mode. So you can not carry multiple modes of light down a fibre that only supports a mode.

You can use multimode fibre to connect singlemode interfaces but this will only work over a short distance. Soon you will encounter some sort of dispertion so its not really recommend but it will work as a last resort.

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  • thank you for your answer. looks like i have some interfaces to acquire.
    – doyle
    May 21 '15 at 13:00
  • @jwbensley "You can use MM to connect SM but only short distance" can you share some experiences and distances?
    – EDP
    Aug 23 '15 at 14:44
  • @EDP sorry I can't, it works in the lab, but beyond that I don't ever do this in production.
    – jwbensley
    Aug 23 '15 at 15:22
  • @jwbensley I was neither suggesting, assuming nor hoping you would :-). I was just curious.
    – EDP
    Aug 24 '15 at 9:48
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Multimode and Singlemode fibres have very different dispersion characteristics, so they are not directly interoperable. In the unlikely event that you can make it work, don't count on it being reliable. You will need a suitable converter.

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  • thank you for your answer. looks like i have some interfaces to acquire.
    – doyle
    May 21 '15 at 13:00
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No, you can't use multimode transceivers with a singlemode fiber plant. This simply will not work as desired.

It is possible to use singlemode transceivers with a multimode fiber plant. This can be more complicated to avoid problems and/or damage to your optic and may require the use of a Mode Conditioning Patch Cable. Make sure to do your research before trying to implement.

Of course, if you are only talking about Gig speeds, in my opinion it isn't worth looking into the MCP cables as they can cost more than buying SX transceivers themselves.

1
  • thank you for your answer. looks like i have some interfaces to acquire.
    – doyle
    May 21 '15 at 13:00

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