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I have bought two WS-2948G switches from cisco for a lab. I now need to buy two additional modules for them WS-G5484. I've never worked with fiber so I was wondering if there are differences in fiber cables and what type of fiber cable I should use on these?

I noticed that there is LC, SC,ST,...

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up vote 3 down vote accepted

For 90-95% of the time basic MM OM2 or OM3 LC-to-LC will do just for all manner of jobs.

You'll want OM3 for anything =>8Gbps but if it's just for 1Gbps links then OM2 is just fine.

Some manufacturers have stuck with SC and ST longer than logic would suggest they should - Cisco can sometimes be one of these - but basically it all comes down to what transceivers you're using.

In the case of the WS-G5484 it is one of that 5-10% that doesn't use LC, in this case it requires SC connectors and OM3, even though it's a 1Gbps link. So in this case to link two of the same GBIC-based switches you've specified you'll need an SC-to-SC OM3 pair.

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+1 More detail than anyone wants to know: LC, SC, ST are connectors (each is slightly different and incompatible with each other), comparable to C8P8/RJ45 for Ethernet. OM2 is Fiber rated up to 10Gbps at short distance. OM3 is rated for 100Gb at 100m). The OM rating is comparable to the Category ratings of Copper Ethernet, but higher grade cable also allows for longer connections to a limited extent. There are also single a multi mode cable, the main difference is the size and distance it can cover. And to cap it off there's 50 um (orange) and 62 um (blue) size cable, OM2+ is 50, usually. =] – Chris S May 13 '12 at 15:06
In my experience the colors are the other way around. 50 micron is blue and 62.5 is orange. – resmon6 May 14 '12 at 18:36

The 5484 is a multimode GBIC. As stated the correct termination is SC-SC. At 1G speeds there is no particular benefit to OM3 fiber - standard FDDI grade 62.5 micron cable (OM1) is good for 220m while 50 micron cable (OM2 and better) all rate out at 500m.

If you are building a lab then pick up cheap 62.5 fiber - plenty of sc-sc to be had on the surplus market.

Nb orange cladding is standard multimode, yellow is single mode and turquoise is OM3 10ge optimized. Keep in mind that there are plenty of patch cables out there in different colors. Always read the cable to be sure.

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