sundance-communications.com Forums Telephone Services Cabling Telephones Systems Wiring How to choose fiber

I usually use multimode fiber, for the short, small jobs I do involving fiber. OM3 I believe. I get a media convertor with matching connectors and we're good to go.

The IT guy is getting involved in my latest fiber project and he has shown me some fiber modules for his switches, and asked which one to use. I asked my fiber supplier, and they aren't committing either way. They say it's up to what they are going to connect. Here's the info:

SFP transceiver 1000Base-SX - LC multi-mode (up to 1640 feet).
SFP transceiver 1000Base-LX - LC single-mode (up to 6.2 miles).

IT guy says the single-mode is only $20 more, so why not get 6.2 miles worth for the extra $20. (I don't think that's the way to spec out fiber ).
My fiber supplier says it depends on what they are going to connect. Just LAN computers, IP phones, general stuff.
There will be three runs, the longest single fiber run will be <500 feet. All in new surface conduit inside the plant.

How do you choose?
Thank you.

Jim

All of my fiber installs are less than 1500'. we always use mulit-mode OM2 or OM3 grade fiber. I don't think my eyes could handle 9 micron single mode terminations.

Why? Because you can overload the receiver causing issues and potentially lower its life. No different than anything else.

OM2, OM3 or OM4 should be fine. with OM3 and 4 you are getting 10gig speeds.

Jim you don't state the length that you need to run or the equipment it's connected to.

When in doubt leave the decision making to the professional, not the IT guru.

For that distance, an OM3, OM4 or SM will work. If this is an existing site (or campus) that you're adding on to, I would go matches the current infrastructure the most. If you have 90% multimode, then use multimode. If you have mostly singlemode than go with that. That will allow you to stock one component for backup verses two, etc...

My opinion is to use single mode. As time goes on and bandwidth requirements increase (10 gig/40 gig/etc) multimode begins to show its constraints.
They make low powered SFP's that would work here or you could simply put an attenuator on it if you were worried about the signal being too hot.

Thanks for all the input. The IT guy and me have agreed on single mode. There isn't any other fiber in this facility, so this will set the standard for this site.

Thanks again.
Jim

Single mode is nice because you can get Bi-Directional SFPs and make better use of fiber strands. One strand, bi-di. Leaving a 2nd strand for backup or future use. Single mode bi-di SFPs are silly cheap too. FS.com has them and I've used them. Works fine in Cisco after you run the non-OEM command. You'll still get the readout on light levels.