atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Splitting a CAT5 for voice and data

Skip - wish I could, cinderblock walls between the four rooms and a hard top ceiling make that too much for today's goal. I told them I could patch it in for now using homemade splitters but that we have to make it right later and that next time I need more than 12 hours notice.

A lack of planning on their part does not constitute an emergency on mine. I know you are just trying to help the customer out but how did these offices get data cable and no phones to begin with.

We can all go on about doing the proper practices (which I believe in) and tell the customer the problem is theirs, but busting everyones balls over this won't get the job done. Yes, you can use the unused pairs. I've done it. Explain there is a slight risk. They will say "Whatever, just get it done", and you'll do the work. Everyone should be happy.

Richard

If the computers are using 1000base-t you're SOL. That scheme uses all 4 pairs.

Can you place a switch AND a wireless router, and use one Cat5e for the 'puters, and the rest of the wires for the phones, as suggested above?

It's more than just a slight risk. Say you split a run and the client decides it's good enough, it can stay that way. You can explain the risks and limitations all you want, the client won't remember that. A year down the road they have some IT company upgrading their network, and they realize they can't do gigabit on some of their runs. Now they're being told "Hey, whoever you paid to install these runs cheated you and did things completely against standards. We can't use these, you need more cable run in." Now you look like the bad guy, and your reputation is damaged. Call me paranoid, but this is reason enough to never do this. If you're really painted into a corner though and it must be done, make sure it looks temporary. Don't do such a good job that the client doesn't want to pay for things to be done right.

there are actually adapters out there that you plug in on both ends of the cable its like a t adapter and it gives a 10 base t and a rj14
I think you can get them from jennsen real labor
savors for a tempo pinch!!

also see page b36 of hubble catalog!!

have done it with digital phones under duress
and never had a complaint about network issues

Well it is done, and so far no complaints. I just yanked the CAT5 jack, pulled off the blue and brown pairs and terminated them to a CAT3. Then on the patch panel I made a Y-cable splitter with a CAT5 RJ45 connector and a CAT5 and CAT3 keystone for each of the 4 runs. It doesn't look half-bad but I put a label on one of them that said "temporary." We'll be dragging a lot of cable in the months ahead so it'll all get fixed then and I can recycle the jacks so it made sense from that point of view as well.

That is not surprising. For 10baseT, based on what the IEEE 802.3 specs say, it was actually designed to operate on existing "category nothing" telephone cable, with phone lines in the same cable, and the potential of interference was taken into account.

For 100baseTX, the situation is not so clear, but the IEEE 802.3 specifations make a point of stating that 100baseT2 and 100baseT4 are not compatible with POTS in the same cable, but ARE compatible with BRI ISDN in the same cable. They make no such statement for 100baseTX regarding compatibility with other services in the same cable.

That they make no such statement for 100baseTX indicates that they do not believe running 100baseTX with POTS in the same cable to be a problem.

100baseT2 and 100baseT4, by the way, are specifications for 100 megabit Ethernet over 2 pairs of cat 3 and 4 pairs of cat 3 cable respectively. It would be reasonable to believe that these are more sensitive to interference than 100baseTX due to the higher data rate running over a lower-grade cable.

As a side note, I've never seen any 100baseT2 or 100baseT4 equipment. I don't think any was ever made.