UGN Security

1000Base-LX Min Length ???

Posted by: hyperx

1000Base-LX Min Length ??? - 09/01/05 01:20 PM


I haven't posted here in a long time~
Just a really quick question! I recently purchased a Cisco 1000Base-SX GBIC for my Catalyst 5500 Sup Eng, but they sent me a 1000Base-LX GBIC instead, I can either send it back or keep it, but I remember hearing something about LX having a minimun length of like 20mtrs or something like that. Which is no good to me, hence the reason I ordered the SX module.

I have looked around for the info about the min length of LX fiber but cant find it anywhere

If anyone knows, could they please tell me what the min length for LX is, because i really don't want to wait to re-order the SX GBIC.

Ashley M.
Posted by: Infinite

Re: 1000Base-LX Min Length ??? - 09/04/05 02:56 AM


Here's the data sheet:

I don't see anything about a minimum distance...

I do remember when I was in school one of my instructors was trying to get a 1000base-something to work, but was having all kinds of trouble (it was fiber, I know that for sure).

In the end he had to back the connectors out of the socket a tad to weaken the signal strength as it was too strong for the receiving end. It was a very short run (6 feet-ish I think)


Oh, there it is. It is on that page I linked to:

Table 1 provides cabling specifications for the Cisco GBICs that you install in the Gigabit Ethernet port. Note that all Cisco GBICs have SC-type connectors, and the minimum cable distance for all GBICs listed (multimode fiber [MMF] and single-mode fiber [SMF]) is 6.5 feet (2 m).
Posted by: Gremelin

Re: 1000Base-LX Min Length ??? - 09/04/05 04:14 AM

I talked with Learner last night and we decided that in all honesty there CAN be a minimum distance, in the conversation we figured the minimum would be something of 5-10 feet; so I supose that the 2m length is fairly close to our guesstimate...
Posted by: §intå×

Re: 1000Base-LX Min Length ??? - 09/04/05 01:05 PM

You might be able to also get a pad to put over the connector. At verizon we use dampening pads all the time. They usally come in -5db increments.
Posted by: Gremelin

Re: 1000Base-LX Min Length ??? - 09/04/05 09:54 PM

Ya know, I still say it would have been funny to say the minimum was 1 mile (1.61km) ...
Posted by: hyperx

Re: 1000Base-LX Min Length ??? - 09/05/05 11:57 AM


Thanks for the help you guys.
I'm gonna keep the LX GBIC and hope that it 'does' works under 3mtrs.

Hah, yeah Gizmo that's what I was hoping nobody would say, and yes it would have been you, not me

Thanks again,

- me
Posted by: §intå×

Re: 1000Base-LX Min Length ??? - 09/05/05 01:43 PM

The link above is a quick view of how you can get around min length cables. Now this is not for your device, but I am sure if you look around you can find pads or couplers that can dampen the strength if needed.
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