LX Media Type

Unanswered Question
Jun 8th, 2008


I have an LX transceiver plugged into an GBIC. I enable this port, but there is no laser beam. I checked this issue on a SX transceiver and I found laser beam. I do not know it is a normal situation on my LX transceiver or not.

I have this problem too.
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Tom Randstrom Sun, 06/08/2008 - 07:25

This could be the result of a couple of issues:

1. The GBIC-LX is broken. Can you install the LX in another piece of equipment to see if it functions?

2. Does the equipment support ALS (automatic laser shut down); which shuts down the laser in event of a loss of signal? I don't think this is the issue because the SX is functioning.

3. The GBIC-LX is not Cisco approved and is being shut down.

Hope this helps!

Tom Randstrom Sun, 06/08/2008 - 08:40

I failed to ask, how are you determining you have laser beam? Are you doing a simple loopback using a short patchcord from transmitter to receiver on the GBIC? Or, are you testing with an optical power meter?

The SX GBIC requires multimode fiber and the LX is used on singlemode fiber.

Sushil Kumar Katre Mon, 06/09/2008 - 04:15


Probably that's the issue. 1000base-LX works with single mode fiber. Check the cable you have.

-> Sushil


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