singlemode-multinode sc to mt-rj

[fs483]

Hello,

This thread is similar to a previous regarding connecting 2 switches through fiber from 2 buildings except different contractors/suppliers are telling different things and I'm getting really confused.

Cabling company installed Singlemode fiber between 2 buildings about 1km apart. They have SC connectors on the break box.

I purchased 2 Cisco WS-C2950SX-24 switches. They are 24 port 10/100 + 2 1000mb fiber uplink ports with MT-RJ connectors.

The cabler left us 4 SC-SC patch cords but we had requested SC-MTRJ patch cords. After calling the cabler, they said since the fiber was long, they used singlemode fiber and if you use a SC to MT-RJ patch cord it would not work and therefor will not exchange the cable. IS this true ?

I then called a telecom parts supplier and requested SC to MT-RJ patch cables which they have but then said that I must know if my switch ports are multimode or singlemode. He said most internal equipment is multimode. Is this true ? He asked me to find out what is the GBIC that is installed in my switch. Unfortunately the switches are offsite and don't have access to them right now. He said that converters *might* need to be installed and that they are pretty pricely. However he said that singlemode fiber to multimode switch port is ok with a direct patch cable. Then he said if the switch is multimode, what size of patch cord do I need 62.5micro or 50micro and also said that 50 micro is preferred. Singlemode has is only 9micro right ?

So I need to know what kind of patch cord/adaptors would I need to connect switch to patch cord to fiber to patch cord and back to switch! I never that it would be this complicated. I want to avoid replacing the switches. It would mean a lost of over 3000$.

Meanwhile I try to get more info regarding fiber interconnexions...

thanks
akwong

 

[dhnl]

Your switch has 1000BASE-SX fiber ports. You will likely need 1000BASE-LX ports. I suggest purchasing switches that will accept a GBIC or SFP module. You can then install modules appropriate for singlemode.

 

[dhnl]

For example two 3COM Superstack 3 3226, two 3COM 3CSFP92 and two LC to SC patch cables will work great.

 

[oldtimerbob]

Now the only thing left that you need to know is what size the fiber is....62.5 or 50 micron. Find out from the installer and away you go.

Good luck

 

[fs483]

I though singlemode only had one size.

 

[dhnl]

62.5 vs 50 is only applicable to multimode.

 

[Jtodd]

akwong, it looks like you've got a problem...

Your switches are multimode switches (based on the SX in the part number) and you've got singlemode cable. First order of business would be to determine which the contractor was specified to put in, and with the 1km distance, it was most likely to be singlemode.
In that case the switches should have been 2950G which would have given you GBIC uplink ports and then get the LX (singlemode) GBIC in what ever plug config is available (my guess is they would be duplex SC).

But since it sounds like all has been purchased, your only option (besides replacing the switches) is a multimode to singlemode media converter (as seen here from Transition Networks):

http://www.transition.com/Transitio...mily.aspx?Name=F-SM-MM-04(xx)+&+SFMFF1xxx-22x

Justin T. Clausen
Physical Layer Implementation
California State University, Monterey Bay

 

[Jtodd]

Sorry, for some reason the full link didn't take. Anyway, here is the full link again.

[link]http://www.transition.com/TransitionNetworks/Products2/Family.aspx?Name=F-SM-MM-04(xx)+%26+SFMFF1xxx-22x[/url]

Also, this should solve your patch cord issue as well, though now you will also need multimode patch cords. Since you'll be patching equipment (media converter) to equipment (switch) it won't matter if you get 62.5 or 50 micron.

Justin T. Clausen
Physical Layer Implementation
California State University, Monterey Bay

 

[fs483]

We've solve the problem with fiber to copper media converters. We are using only the 100mb copper ports. I didn't see any performance problems. If we ever need to add new switches, we will then purchase the models that work with singlemode and use the fiber ports. I haven't seen the quote myself but the original plan was to have the fiber buried. Then later, they (the contractor) decided without notifying us to have the fiber strung along the telephone poles making the fiber much longer then it was originally planned. This is maybe the reason why they switched to singlemode. The boss of the cabling company saw the switches before having the cable installed and said everything would be fine. Anyways, it costs us about 1000$ more for 2 fiber/copper converts (about 250$ each) and 4 hours of consultation fee at 100$/hr. We even had to go on site because the tech that they sent didn't even know how to press on the ON button on the surge protector ! At 100$/hr to plug in 2 fiber converters, I was expecting a little dance or something would be included... Our second mistake... Hey at least I learned a couple of new things on fiber for this project.

Case closed.

Thanks for all your help.

 

[askthetech]

Bigger is better. Email me later and I will look for you what size would be the best for you per the CAT6 book. Can't remember off hand, unless you want the CAT5E code?