Sharing one Cat5/6 Cable for Internet/Phone

The phone line only requires 1 pair, but ethernet usually requires 2 pair. So you can run both over the same cable, but the pairs would need to be split.

Standard 10meg and 100meg ethernet use the orange and green pair. So the blue and brown pair are available for phone lines. However, you would want two jacks in the wall plate one that has the orange and green pairs wired for internet in an RJ-45 jack and one with the blue and brown pairs on an RJ-11 Jack. On the other end, you would need to split the orange and green pairs from the blue and brown pairs as well.

I wouldn't recommend this if you are running new wire, however it works fine if you can't run new wire.

A major caveat... Gigabit Ethernet uses all four pairs so this won't work for gigE.

Don't understand why he's reluctant to run more than one wire since CAT5/6 wire is so cheap. Seems it's just good practice to run separate wires for each. That avoids any possible problems.

That's what am afraid of too.

Now FIOS currently seems to offer a 50mbit service, and u'be fine with a split pair, but to futureproof, I would go ahead and tell the contractor, lay me a CAT6. He's gonna charge u for the xtra run of course.

As said 10/100 mbit Ethernet only uses 2 pairs. But u definitely want to run CAT6 (CAT5+?) inside the house between nodes and the switch for gigabit.

As already mentioned, by only using 1 wire for both phone and network, you'll be limiting yourself to a 10/100 speed network. 10/100/1000 networks do reguire all 4 pairs of wire in a cat5e or cat6 wire. Just because your internet speed might not be gigbyte speed, that doesn't mean that your internal network won't eventually need gigabyte capacity. As you add more computers or send large files (like media files) between several machines, you'll want the faster network capacity.

Also, when a phone rings, it sends a much higher voltage signal down the phone line to power the ringer. This can cause interference in the network lines since they are intertwined together in one wire.

I'd tell the contractor to run two wires instead of one. It will be worth the extra cost in the end IMHO.

On this, buy a switch and locate it next to your router. Connect the uplink side of the switch to one of the ports on the router. Then you can wire up as many ethernet jacks as you want, limited only by the size of the switch (24 port? 48 port?) and your willingness to keep buying switches.

As for the wiring, what everyone else said.

Some additional comments on what has already been said.

Not only will the ring voltage cause interference, it can actually cause damage to the devices using the other pairs in the cable bundle for network connectivity. The ring voltage is large enough to induce a spike which can be very damaging to the network gear attached to the other pairs. I ran into this dilema when I only had a single Cat5e drop to a corner of a new office for a network printer. I had no plans to purchase a multi-function printer but ended up getting one. So it was a choice of splitting the cable pairs to allow for phone and ethernet connectivity. I decided in the end to suck it up and pull another drop just for the phone connection.

As for expanding additional network ports, yes, you can just use a switch. Now a days, you don't find many network switches with "uplink" ports. Pretty much all current switches have ports which are MDI/MDI-X capable. This means the switch can negotiate with another network device over which one has to flip the receive/send pairs or can just do it itself when the network device is not capable of this. This negates the need for crossover cables or a button which you would push for the dedicated uplink port to do the flip. Uplink ports when they do exist now is when you are cascading network switches where you want a higher bandwidth connection between switches. This helps in alleviating any bandwidth contention when you have say a 12 port 10/100 switch uplinked to another 10/100 switch with only a single 100 Mbit connection. Obviously you can see that if there is a lot of traffic, you are limiting all attached devices on both switches to just a single 100 Mbit connection. Uplink ports on these type of switches are GigE to alleviate this congestion. On GigE switches you don't see uplink ports anymore except on higher end business grade switches. This is because the next step is to go up to 10Gbit which no one in home environment has the infrastructure to support. There is one exception to this for GigE switches for uplink connections. Some GigE switches have SFP ports which you can connect a fiber transceiver so you can span long distances for your uplink connections between switches.

With the above said, it is a good idea to think about how you would lay out your switch infrastructure. The best thing you can do is to have all network devices talking over the same switch backplane. All switches have backplanes which have more than enough bandwidth to accommodate heavy loads for the given number of ports. You always want to utilize this aspect when building out a network. If you have a current requirement which only needs 12 ports, it's a good idea to buy a switch which at a minimum has 16 ports. What would be better would be 24 ports. This way you have the ability to expand out without the need to cascade switches or spending the money to upgrade the current one when you run out of ports. There is another way to get around this performance issue when linking switches but this requires managed switches and the use of Etherchannels.

There have been some good responses, but I thought I would give you another explanation. Your installer is running one Cat5/6 to each room, but each Cat5/6 has many small wires inside it. Then right before the wall jack, he'll split up the small wires, some for phone and others for internet. But all you see from inside the room is two jacks, one for phone and another for internet. If you unscrewed the wall plate and pulled it out, you would see how he split the wire.

As some have said, this eliminates your chance at having a high speed gigabit ethernet network, and can cause other problems.

If it is a new house and you have the means, I would run at least two wires.

I'm hardly an expert but want to add a few things to this thread.

I know running separate wiring for voice and data is the proper way but what if it is too late.

When my house was built, they used CAT5e for telephone. I had a chance to wire whatever I liked but I cheaped out and didn't run two drops of CAT5e for every room. I only did two drops to just three rooms. Like everyone has stated, I don't know why I didn't do it but I totally regret it now.

Anyways, I put in a structured panel and knew that one day I would be changing some of these voice lines to data.

When I called the guy to rewire my house, he mentioned I could do data and phone over one CAT5e. I was happy to discover this as some of the rooms were not so important to have gigabit speed.

I have tested the lines where the cable is shared and I don't have any interference. I get constant throughput (pretty much full 100mbits/sec) while transferring files when the phone rings or when in use. No problems what so ever.

I think this is done in practice quite a bit. There is a lot of reference to this on the internet.

Here is a quote someone from another forum:

"I have had to mix Ethernet and POTS phone lines on a single CAT5 cable many times. Never had any issues yet what so ever.
Just keep pairs separated for Data & Phone. I usually use the Green and Brown pairs for Data. Using 586B punch Green on Green and Brown on Orange.
Note this will only give you 100 Base TX, you cannot use POE (Power Over Ethernet) or 1000 Base T in this configuration.
Not ideal, however, many times this is better than wireless and saves time when there are not separate Voice & Data drops."

Basically, doing voice and data on the same CAT5 cable can be done but it would be "non-standard" so you have to be careful not to make a mistake and there would be caveats -- especially if someone decides to make an application that would make use of the unused pairs in 100 Base TX. And of course, Power over Ethernet would be impossible and extremely dangerous.

(As a side, I don't get how they can do PoE yet people here are worried about phone ring voltages)

In the end, the cost of labour to have someone do work on my CAT5e lines is more than what it would have cost me to put almost another 10 drops of CAT5e when the house was built. So I should have went nuts wiring everything imaginable.

Phone ringer voltage is somewhere around +90v, and (speaking from experience here) is enough to shock you if you happen to be working on the phones when someone dials in...

LOL, my first custom wiring job back when I was a teenager was a phone system. I learned about the "shocking" results of a ring while wiring the hard way...

Ring voltage is 90VAC, POE is DC.

The short answer is just say no. Run a dedicated cable for ethernet (you will definately want GiGE) and whatever else you need for phone, TV, lights, other automation, etc.

Ring voltage is 90VAC at 20hz.
Talk battery on-hook is 48 volts.
Off hook (dial tone and voice) voltage is 5vdc.
Positive side is green, ground side is red (opposite of what you would expect.

New phones with piezo ringers and not actual bells do not induce major current spikes on the line during ring cycles and as such are generally OK in CAT5 cabling with the 2 ethernet pairs in use.

Many homes are wired with what LOOKS like unjacketed CAT-5 but it is not. The unjacketed multi-pair cabling is called E-station. It is a CAT3 cable, not suitable for ethernet use. It was designed for multi line phone installs or, in some apartments, the pairs are split between adjacent apartments.

I never cease to be amazed at how cheap contractors can be. When I hear about this type of thing I always want to know where else they are saving a few cents? Heck, why not use 2 x 6 where the engineer specified that 2 x 8, it should work, right? Sorry for the rant but put a boot up this idiots ass and tell him we aren't still living in 1970 and that nowadays folks like to have one cat 5 for network and one for phone (unless of course you have a VOIP system).

Because the structured wiring should be "Builder Grade" just like everything else in typical residential construction!

There is no positive....it's -48VDC WRT ground.

yea. We are talking voltage across the line pair, not earth.

uhhh, yeah...one of those wires is grounded (earth)...the other is at a -ve potential relative to it (earth)....so, "we're" talking about the same thing.

Yes you can run phone with data with cat5. there are 4 twisted pairs in a cat5 and cat6. You would only need 1 pair for phone. leaving 3 pairs for video or internet (data). I would use blue or brown for phone and leave green and orange for data or video as they are more twisted and less prone to interference, especially over long distances.

Yes you can run phone with data with cat5. there are 4 twisted pairs in a cat5 and cat6. You would only need 1 pair for phone. leaving 3 pairs for video or internet (data). I would use blue or brown for phone and leave green and orange for data or video as they are more twisted and less prone to interference, especially over long distances.

You joined just to reiterate bad advice?
Read the thread for a clue.

TelecomBruce,

This is without question the worst advice I have seen on AVS. Seriously, don't ever repeat this advice.

Yes, you only need two pairs for 10/100, but there is a reason why Cat5/6 cable is not referred to as "structured media cable for cheap folks", and that is because 4-pair cable is designed to be run and terminated in such a way as to preserve its data carrying capacity.

According to Cat-5 5e or 6, the un-twisted part of the wires CANNOT exceed 1/2". When you start dismembering cables so that you can connect to two jacks, you will expose about 1.5" minimum, and the wire will no longer be able to carry 100MBs. Yes, you can get around it by properly terminating both ends, then creating a franken-connector to plug into it and split the wire pairs.

So you spend a few hours drilling holes and then decide that running two cables, at $.10/foot, is too expensive? That you would rather create a useless, hobbled network?

Seriously.

And for the rest of us, Cat5 is useful for thermostats and remotes, not networks. Please do not give network advice unless you actually understand networking. Gigabit ethernet is incredibly useful, and easy to impair if you think of Cat6 as just little-bitty versions of speaker wire.

NO, NO, NO. Not for new wiring, anyways. If you had to run both on existing cable, and there was no way to put more in, I'd say make adapters on the two ends, leave the in-wall wiring as 8p8c straight through. These days with DECT 6.0, there is really no reason to even run phone wiring. Run a bunch of 8o8c Ethernet lines to each location with Cat-6 or better, and if, for some crazy reason, you actually need to run a phone line, you can always use an 8p8c connection in the wall with 6p4c phone connections to run a phone line. At this point, if you end up with Triple Play or Ooma something, I'd just put the phone base next to the router and use DECT 6.0 handsets around the house.

Run a separate cable intended to be used as an analog phone line. If you do use it for that, fine. If you don't, you can use it for another network connection, or you can use for any other purpose that might call for 1 or more pairs of wires, such as i.r. remote control extension.

Cable is cheap. Better to build your system the right way than build it in a way that will merely work (while limiting your options) just to save a few bucks.

i have done this very thing before for my own network simply because it will work and i was renting the place of this network and only had one phone line extension. you use the last two pairs brown, Brown/white. the other three pairs w/o O w/g B w/b G are used for the network and will traffic 10/100 across the network. When getting into 1 gig or better cat 6 is required and that's another issue. If you want to use a patch panel or a rack network i suggest pulling another cat 5 cable or a "authentic" phone cable to the same location at the same time the other drop is done. also pull a string in case you want to add another line later.

hope this helps
Wade.

No, use the proper standard which states that the middle pair, which is the blue pair, be used for POTS.

Yes, that's the middle 2 pins on the plug side of the jack. On the cable termination side, it depends on the manufacturer. Some have all of the terminations in a row, while others have blu/brn on one side and org/grn on the other side.

For 10/100 connections, only 2 of the pairs are used for network.

Gig runs on 5e, but it needs all four pairs.