Fiber link issues?

[Shermanchicken]

I have a 6 strand multimode fiber (62.5) at 400 ft. The IT person installed two fiber switches to the fiber. The switches don't get a link from each other. I've tested the fiber results qith a reading of 14 db. Does this measurement have to much loss for the switches to see each other. Don't know if its a switch problem or if I have to reterminate my ends. What would be the minimum acceptable db loss for the switches to see each other and work properly. Thanks.

 

[mikeydidit]

It is either going to the the G bix or the fiber need to be swapped around on one end. If he is using the LX it should support MM or SM fiber. While a 14 DB loss is not good on such a short distance, it should still work IMO. You could reterminate the fibers and should be able to get a lot less loss.

Hell, there are no rules here - we're trying to accomplish something.
Thomas A. Edison

For the best response to a question, read thread690-1323977

 

[SYQUEST]

Make sure the connectors are CLEAN and there is no debris or dirt in the GBICs. Dirty connectors can cause all kinds of loss. To verify continuity you can put a loop on one end and the other should show an indication at the GBIC if you don't have any optical test equipment.

One more thing, one end needs to have the patch rolled, ie: TX -> RX and RX -> TX for the connection to snyc up, since TX -> TX won't work!

Hope this helps!

....JIM....

 

[RobKorn]

14db loss in 400 foot is very high, I think either the test equipment wasn't "zero out" before test or you have some bad termination/fiber.

Check the results from either end, is it better or worse depending on which end of the link you test from?

Try to make the hardware link up "locally" with a couple of fiber patch cables and barrel connectors. If they won't link locally, adding 400' of fiber is not going to help.

As said before, TX - RX must be crossed.

Are the patch cables good?
Same fiber modules on both switches?
Fiber patch fully inserted in device and landed fiber?

Good luck.

 

[Shermanchicken]

Thanks for all the helpful information. I will check for dirt and test the ends both ways. TX and RX are in the correct order. I ordered new ends just in case. Thanks again

 

[dagwoodsystems]

If you don't have a fiber scope (but your eyes are good), use the ol' flashlight trick.