Split fiber into voice and data

[kevnich2]

We are currently in the process of connecting another off-site location to our main office. We'll be connecting this location to the main office via a single fiber. My question is we're wanting the voice (nortel) and data to travel over the same fiber. How is this accomplished? And to answer questions ahead, no, I am not doing this myself. I am hiring a fiber optic installer to install all of the fiber so I won't be touching any of this. I am merely interested in how this is accomplished. I am familiar with CAT5e cabling but have yet to do anything with fiber and an merely interested in how this is accomplished. Any help would be appreciated. Thanks in advance.

 

[spidey07]

Well, if you're running the fiber tell us what kind and how long.

The only way that I can think of to do it on a PAIR of fibers (can't be done with a single, need transmit and receive) would be an optical multiplexer or packetize the voice (voice over IP)

Each of these methods will require serious work/thought and it's impossible to say exactly what you need without knowing exactly what voice equipment is being used and how many calls you need to handle.

If I were you I'd pull 24-48 strands of fiber, the cost of the fiber isn't much compared to the labor. You would have many more options this way like just using a remote shelf over one pair of fiber and then running data over another pair.

 

[kevnich2]

The voice and data are on two separate networks. Voice is nortel digital (not voip) and will be going about 350 feet underground in a pvc conduit. I'm guessing your suggestion is to run one pair of fiber for our voice and another pair of fiber for our data? I'm having our installer pull an extra 2 pair of fiber through so we have extra just in case. Again, I'm not the one actually running the fiber.

 

[kevnich2]

The reason I'm asking this though is because our fiber installer is recommending we use one pair of fiber for both our data and our voice network and using a multiplexer at the end to separate them. My suggestion is to use two separate pair (one for voice and one for data)

 

[spidey07]

Tell your installer to pull 48 strands of fiber. While you're at it, pull 48 strands of single mode fiber. I'd also make it armored outdoor rated fiber since it is in a PVC conduit.

48 strands of high bandwidth 50 micron multimode fiber and 48 strands of single mode.

You could use a mux to get voice and data over a single pair, but why do it? More cost and more complexity. And why am I recommending so many strands? Because you'll use it. What you really need to be doing is two pair for the data and two pair for the voice - that way you have a backup.

If you want to go overboard you'd have the fiber coming on separate paths and separate entrances, but I don't know how much resilliency you need. I just have a do it right and do it once mentality.

 

[cmetz]

spidey07, you can transmit and receive on the same fiber thanks to the wonders of CWDM - this is exactly what BPON / GPON do for fiber to the premesis (home) deployments.

But just having a bunch of single-mode fibers is clearly the best long term solution.

 

[skyking]

350 ft is cake for digital phone systems. Most systems are good for 800 ft or more, and I've run comdial DXP/DSU/DSUII out at 800 with no problems. If you are not routing a ton of stations, copper for the phones would be more cost effective.
25 pair is around $0.30 a foot, or $100 for the wire, and a couple of 66 blocks at $10 each and your job is done.
All the fancy fiber hardware will add up rather quickly.

 

[cmetz]

skyking, you forgot the isolation blocks for the copper lines between buildings. That's an added cost (don't know how much, probably not *too* bad) and important if you'd prefer not to blow up your PBX, and/or phones, and/or employees.

You can do copper voice lines between buildings, but it's a pain for electrical safety and it's a pain to debug. Besides that, if I were building out in a new building, I would not do so assuming that the world is going to continue to be traditional PBX. I'd bet rather heavily on the future being packetized/VoIP. Also, I would not run extensions in building 2 out of the switch in building 1, especially without physical diversity. That's one backhoe (or aggressive groundhog) away from disaster. And now, PBX systems are getting cheaper to the point where putting one in each building and interconnecting them is a good architecture (that used to be cost prohibitive).

I admit to not knowing the part and price off the top of my head, but there's gotta be a widget for modest cost that takes a four-wire T1 in and connects to a full-duplex SMF pair, such that another of these widgets would convert it back. Then you do a T1 or PRI trunk between your old building's PBX and your new building's one.

 

[skyking]

I suggested copper based on the premise of routing a few stations from an existing PBX. It is the most foolproof and cost effective way to do so. I had forgtten to mention the isolators, they are about $10 per pair for both ends.
I would suggest that sufficient data capability is installed on that initial deployment, something like spideys' multiple fiber suggestion. That will cover any future VoIP possibilities. For now, it sounds like they need a few drops out there, not an entire PBX.