Fiber Switch compatability with 50 micron fiber

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Apr 3rd, 2009
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I have a WS-C3550-24-FX-SMI fiber switch and it was being used on a 62.5 Micron fiber infrastructure. The office moved to a new facility that has a 50 Micron fiber infrastruture. Can I still use the same switch and what problems will their be if I do use it? Thanks.

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viyuan700 Fri, 04/03/2009 - 13:53
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Yes you can use the same switch over 50micron fiber without any problem.

Only problem (in your case in fact it is advantage i think)you get more distance

For example,

WS-G5484 1000BASE-SX

card can go 220-275m for 62.5Micron finer but for 50 micron the distance is 500-550m.

You can see this link to see distances for other cards

et1foster Fri, 04/03/2009 - 13:59
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Thank you for your answer. Now can you use a 62.5 micron fiber patchcord from the 50 micron wall jack to a Cat5e media converter?

viyuan700 Fri, 04/03/2009 - 15:27
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Are you going to connect Gigabit card in your switch to the Media Converter by a 62.5Micron Patchchord and in between fiber is 50Micron?

If i have understood corectlyand your setup is like this

switch -62.5micron Patchchord -50Micron Fiber- Media Converter


Switch- Media Converter -62.5 Micron Patchchord-50Micron Fiber

I dont see see any problem in any of the above setup if distance is well within the limits.

ONLY problem i could see is that you will get a shorter distance when you are mixing 62.5Micron and 50Micron than when you have all 50Micron.

et1foster Fri, 04/03/2009 - 15:41
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It will be connected like this. Switch-50 Micron patchcord-50 Micron fiber infrastructure-62.5 Micron patchcord-Media converter-Cat5e to desktop. Should not exceed 200 meters.

viyuan700 Fri, 04/03/2009 - 15:46
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Few meters of 62.5 Micron Patchchord will not be a problem i think if distance is within 200meters.

Your setup should work.

R u using WS-G5484 card in your switch?

et1foster Mon, 04/06/2009 - 07:01
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Yes, but only to connect the switch to a Cisco 3825 router and to connect to another fiber switch. The fiber ports that I'm asking about, are the 24 ports on the switch. Not the GBICs. The 24 ports are permanent MTRJ ports. Can't be switched out.

Tom Randstrom Mon, 04/06/2009 - 07:45
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Although it is technically feasible to combine 50 micron and 62.5 micron core multimode fibers in the same system, there is a one-time attenuation loss when coupling 62.5 micron fiber into 50 micron fiber.

Given the reach of a 100Base-FX link (2km), there is a good chance the system can overcome the additional loss at the 50 micron/62.5 micron interconnection. You can always replace the 62.5 micron jumpers in the event the system is not functioning properly.

viyuan700 Mon, 04/06/2009 - 07:50
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these are the type of 24 FX ports used on 3550 and on 62.5 & 50microm can go till 1.2miles (2Km).

Power is lost when you connect fiber of Different diameter like in your case from 62.5 to 50 since your distance is within 200m so should not be a problem.

et1foster Mon, 04/06/2009 - 07:56
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Thank you for your answers. It was very helpful.

Tom Randstrom Tue, 04/07/2009 - 10:04
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After your transition, let us know how it worked out!


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