Fiber loopback adapter

Posted on 2011-10-31
Last Modified: 2012-05-12
I have a fiber loopback adapter with an LC connector.

What can I do with this?

If I plug into an SFP on a switchport then spanning-tree blocks the port so I don't know how that is useful.

Is this loopback more for fiber installation, repair and testing.

It is a cisco branded loopback adapter.

Marked ADP.OPTI.LC.LOOPBACK.ATT5dB Cisco PN 39-0234-01

Just wondering if I would have any use for it if I am not installing and testing fiber optic cables?

It is also has a test sheet that shows:

1310nm, insertion loss 5.23dB and return loss 55.8dB.

1550nm, insertion loss 4.85dB and return loss 55.9dB
Question by:Dragon0x40
    LVL 11

    Accepted Solution


    you can plug one connector to the input port and the other one to the output port for testing.

    Fiber Optics Loop back adapters are designed for testing. Optical loopback adapters provide system test engineers a simple but effective way of testing the transmission capability and the receiver sensitivity of network equipment.Fiber optics Loop back Modules are also known as Fiber Optics loop Back Adapter.

    Fiber Optic Loopbacks are designed to provide return patch for a fiber optic signal. They are used for fiber optic testing applications or network restorations.

    In testing applications, loopback signals are used for diagnosing problems. The best practice is to send a loopback test to network equipment, one at a time for isolating the problem. you can try with your adapter to check whether it is ok or not.

    This optic loopback modules are made with a variety of fiber cable jacket types and cable diameters.


    Author Comment

    I assume that I would need some test equipment such as and Optical Time Domain Reflector?

    Is there a troubleshooting purpose for these adapters or any other purpose that they can be used for?

    I don't have any fiber testing equipment so if not then this is probably useless for me?
    LVL 11

    Assisted Solution

    OTDR is a fiber testing equipment......
    i think you may test fiber module..patch cord and other fiber components.....if you don't have OTDR ..then you can purchase a power meter..through power can test a signal..whether it is passing or will not get detail report like OTDR ...but you will get the report...whether signal is passing or not atleast.

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