We have single mode OFC network and CAT 6 CAT5 LAN with ethernet and gigabit Ethernet switches and ordered for "GE SFP, LC CONNECTOR LX/LH TRANSCEIVER FOR SINGLE MODE FIBER OF CISCO CATALYST 2960 S" SWITCH but the supplier has delivered "GE GLC SX MMD" Now what to do with this because the switch is not working with this transceiver What type of mode conditioning patch cable or other cost effective fix and all possible alternatives to make GLC SX MMD work with CATALYST 2960S SWITCH and single mode OFC .What will be the configuration.Please help and advice

  • You are basically saying that you ordered a vehicle with a gasoline engine because gasoline is the only fuel available to you, but the dealer shipped you a vehicle with a diesel engine. Now, you want to know how to run gasoline in a diesel engine, and the answer is that you cannot.
    – Ron Maupin
    Commented Nov 21, 2018 at 23:25
  • many thanks for your correct but i wish that you could with some good news that will not sound so bitter but life is such that you will have work with bitterness.Many thanks your answer both your full answer and comment. Commented Nov 24, 2018 at 16:27

2 Answers 2


You have a multi-mode transceiver, and it will not work with single-mode fiber, and it uses a different wavelength than what you are connecting to on the other end. There is no configuration to make it work, except with multi-mode fiber.

Call the supplier and have them make it right.

See Cisco SFP Modules for Gigabit Ethernet Applications Data Sheet:

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In fact, it can but you donot have to. To use SMF in a MM SFP, you get a shorter transmission distance and a possible higher bit error ratio.

  • "In fact, it can..." No, SX at 850 nm cannot communicate with LX/LH at 1310 nm. You cannot have SX on one end and LX/LH on the other end and expect them to communicate. There is no possible configuration to make it work.
    – Ron Maupin
    Commented Nov 6, 2020 at 19:43

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