Hack your House: Run both ethernet and phone over existing Cat-5 cable

The new fad when building a house is to run Cat-5 cable to every wall jack. These jacks can then be used for either ethernet or phone. When we got our new house built, we chose to get four of these jacks, and we intended to use them for phone service. Unfortunately, the wifi is a bit flaky in places (even with two access points.) This got annoying up until the point where three of the four wall jacks were being used for ethernet, leaving just one for phone. This was a problem.

The solution is to run both ethernet and phone over the same existing cat-5 cable. Every wall jack becomes two jacks, one RJ-11 for phone and one RJ-45 for ethernet. This neat hack could save you a lot of money, as you only have to buy new wall plates and jacks rather than wall plates, jacks, and hundreds of feet of wire.

See how this works in the next step.

Disclaimer: I'm not sure if this is legal. The telephone company won't be pleased if you short your telephone wires together. However, if you do everything right, they won't care. Don't blame me if you shock yourself (unlikely), damage Ethernet devices (also unlikely), damage phones (not as unlikely), damage your house wiring (not too unlikely), or damage your fingers with knives (rather likely).

Step 1: Theory

This is made possible because of the wasteful (some may say "spare") wires in cat-5 cable.

Cat 5 cable and RJ-45 jacks have eight wires.
Ethernet uses two pairs (four wires), one for send and one for receive.
Telephones use two wires.

Therefore, you can run both ethernet and telephone over the same wire, and still have two wires left over.

In fact, you could run two Ethernet jacks from a single cat-5 cable, or four telephone lines (though I don't know why you would run multiple phone lines.)

This Instructable will focus on changing wall plates from one RJ-45 (Ethernet) jack into one RJ-45 and one RJ-11 (phone) jack.

Note that I have not done extensive testing with cross-talk between phone and ethernet, though I have seen no degradation in the quality of either when both are in use.

Also note that this procedure will not work with PoE (Power over Ethernet) devices. Nothing bad will happen, it just won't transmit power. See step 13 for a possibly unsafe way to keep your PoE and add phone service. Also, it will not work with gigabit ethernet-- gigabit ethernet uses all four pairs. It will work fine at 10/100 Mbps which is sufficient for most people.

Comments

[leonthedruid]

Keep in mind this will work for 10baseT and 100baseT but in no way compatible with Gigabit Ethernet.

[simdude2u]

But you can't run gigabit ethernet!! because gigabit ethernet uses all 4 pairs of wires.

[Stonie]

Hey nice post!

Lots of good information in the comments too ;)

One question: Given that the phone line is 'live' is there any problem soldering it? with an iron that is earthed?

I have 3 Irons, one is an ESD safe station, second a Goot 12watt and a el cheapo 25watt, all three have an earth pin on their wall plugs?

I guess earthing the live wire is not ideal?

Cheers,
Stonie.

[Stonie]

To answer my own question… I checked with some line techs and apparently MDFs are soldiered live. So earthing via your iron is ok… Also shorting the line (closing the circuit) probably is not a big deal either… at least not in Australia.

[mednasrallah]

You might not know that you can plug RJ11 plugs into RJ45 sockets, it's specifically designed like this. So your 2nd socket could be an RJ45, this could be a bonus depending on how easy it is for you to find RJ11 sockets.

Only downside to this is someone trying to plug a computer etc into it.

Ideally should have double cable runs to every panel in a house anyway, and then patch as you need. It's nice to see some places are being cabled like this now - but then seeing single runs makes me die inside ;)

[bshad74]

This is very good article. Thanks. My question is that;

I have no phone at home but have DSL throgh ATT (they call it Dry Loop).

I have my Wireless modem in the home office and connected to phone jack (which is Cat5) in that room and wireless is use around the house (which is wired with cat5 all across).

I would like to use the other jacks in the house as Ethernet outlet to connect my TV media drive to avoid WiFi slowness. they are connected through wifi. How do I connect my cat5 phone jacks to my modem while continue to receive dsl connection?

How do I do that?

[T3Hprogrammer]

First, you should move your DSL modem into the Cat-5 junction box, which is hopefully the same place that your DSL comes in. Then, you can rearrange the cables so that the DSL goes straight into the modem, and the modem's ethernet goes into the wires that lead to the rest of your house.

If your DSL comes in nowhere near your junction box, and is for some reason wired up to one specific jack, then you will need to somehow get an ethernet line between the DSL modem and the junction box. There, you can place an ethernet switch and plug all of the pre-existing wires into it.

[festec]

Lots of all new million $ homes in Calgary only have one cat5e installed for telephone and no data jack? That's not a problem for Contact Direct Connect but apparently it is a problem for the other Contractors they need two cat5 cables for the same level of function at twice the cost..
http://www.contact-directconnect.com/images/Smart-Jack.jpg
Data networking, which should be an inherent capability of a well-designed phone cabling system, its completely unsupported by the common "hard-wired" design. If data networking is done, separate 4-pair cables are run to a modular patch panel. The problem with this is that now some wall jacks are just for voice and others are just for data. Each jack is less powerful because of its specialized use. Total system cost must be much higher for a given level of functionality. The system will work, but is neither structured, nor optimal.

[lperkins]

Rather than hack apart your wires in the wall, you can buy or build what's known as a "splitter." You put one on each end of the wire. They're easily available to split the cable into two ethernet channels, or four phone channels. Making a custom one is as easy as doing what you did here with a short piece of cable and putting a plug on the end of it. Keep the wires as close to their original configuration as possible to minimise the amount of interference you pick up. (Read don't untwist the wires any more than absolutely necessary, and have them fork off from each other at the last possible moment.)

The advantage to doing it this way is that it's not permanent so you can reconfigure your panel any which way you want in the future.

I can probably be convinced to post an instructable about making splitters if anybody's interested.

[goodmike]

There seems to be some basic misunderstanding about how the telephone company gets from its central switching office to your house. First of all, almost all single line, residence phone lines come into your house on one pair of wires. If you have DSL in addition to local phone service, you still only have one pair of wires (identified as "tip" and "ring"). Both voice and data have distance limitations when transmitted over wire...enter fibre optics. The phone companies use fibre optics to overcome the distance and bandwidth limitations of metallic conductors. In my area, something called a DSLM (commonly referred to as a D-Slam) is used to carry voice and data signals great distances from the central office to your neighborhood. You have probably seen repairmen working at a green metal box about 5 feet high, 3 feet deep and up to 15 feet long. That is the DSLM terminal that server the neighborhood. It is fibre optic from the central office to the DSLM, then one metallic pair to the individual house. One DSLM can serve 24 or 48 or 72 or more individual homes. However, at the beginning (the central office) and at the end (your house) you still have one pair of wires.

By the way.  My knowledge comes from a 40 year career with BELLSouth in Florida and North Carolina. 

[pcooper2]

A DSLM or a Remote Concentrator Unit (RCU) make it possible to provide ADSL service to customers who are tens of miles from the central office, where ADSL is usually limited to 18,000 feet.

[shtihl]

if you wanted to avoid soldering, you could pick up a set of Telephone Wire Splice Connectors which are located in the same section of the big box hardware store (starts with HD) as the other parts you will buy for this DIY. they are red and allow you to crimp two wires into one by simply squeezing the splicer with a pair of pliers or the needlenose on your multi-tool

[cowen]

You CAN NOT use this on DATA. To use this on a data cable these untwist the cable. From the above discussion about the need for twisting of the pairs these splices are designed not to work. It is not IF you will have a failure it is when.

[pcooper2]

You CAN use these crimp splices on DATA. Make sure the pigtails are kept as short as practical. The pigtails are an impedance discontinuity in the cable, but as long as one has very few of them and the size of the discontinuity is kept small, most systems have enough tolerance in them to still be able to work reliably.

[T3Hprogrammer]

The method described in the instructable does not modify the twisted nature of the ethernet wires (I was very careful about that.) Be sure that if you use another method (such as these splices) that you leave the data wires twisted up until 1/2" from each termination.

[elias.alberto]

I don't know how different are your phone landlines from the ones in Brasil, but what I've noticed is my phone will work regardless of the polarity of the wires. As long as I connect both, the phone works.

[Dranoweb]

Polarity does matter.
Most phone have polarity correction built in and hence you won't notice any difference on your phone, but your modem and adsl signals will suffer with reverse polarity.

Phone lines are 48VDC on idle, 90VAC on ring and around 30VAC when in use.

you can check with a multimeter but red should be negative (odd but true) and green should be positive.

If you have a second phone line, black is positive and yellow is negative.

[pcooper2]

Phone lines are -48 VDC open circuit. The ring signal is 30-34 VRMS superimposed on the DC, so the swing is roughly between ground and -96 volts.

The old 4-conductor, beige jacketed household telephone cables typically used red and green conductors for the first pair, although this is not true of CAT-5A cable which uses eight white wires with various color stripes. Wire pairs are twisted together in CAT-5A cables.

If you don't know what VRMS means, you have no business fooling with this stuff.

[zydicious]

Wonderful instructable to inform the masses of this. First, this is indeed perfectly legal. When my ex-wife's business moved to newly built premises the jacks were actually set-up for this with only the actual wiring left to do when I set up all of their office equipment.

[roadie.web]

Is there a length limit to this setup? I wanted to hook up my PS3 in my basement to a switch in the upper floor. This means it passes thru 2 floors (Basement - Main floor -Upper floor).

The Cat5 cable I'm planning on using is also carrying DSL signal. However, I'm just going to stream movies to the PS3, that means, when I'm downstairs watching movies, I won't be surfing the net.

I'm not looking for gigabit speed, maybe just 50Mbps for the HD movies that I stream; does it look like it's going to work for me? Thanks.

[T3Hprogrammer]

The length limit for cat5e cable is 100 meters, assuming you preserve all twisting at the terminators (max. of 1/2" untwisted). I would guess that a noisy DSL signal running right next to it would do no worse than halve that figure, so you should be good.

[msalinas-1]

What kind of jack is on the Bottom? That looks like one of those Kwik Jacks. Is that right?

http://www.discount-low-voltage.com/kwikjacksystem.html

[JettaKnight]

This will work in a pinch. However, the noise coupled from the POTS, will induce errors (i.e. slower bit rate) onto the ethernet. It's certainly a good instructable since it's valuable information as long as you mind the caveats. One thing that hasn't been mentioned - lightening. If lightening strikes the phone line or near the line coming into your house it will be coupled on the ethernet; possibly destroying your switches and computers. For my house, I ran separate lines for phone and data. Several locations use the same data cable for two ethernet connections. And the line coming into my house is fiber so I don't worry about lightening, unless it's really, really bright.

[T3Hprogrammer]

This is a very good point-- at our old house, lightning struck our cable line as it entered the house. We have Fios now, but there is still some copper near the house.

[cowen]

GLASS can conduct a lightning strike too. I just finished a project replacing a fiber that was melted by near lightning strike. Not properly grounded it took out the entire run including both closets and all the gear in them. The GLASS acted as a conduit for the strike to follow. Also learned this in a Fiber termination class for FIOS.

[jongscx]

In regards to the POE setup, it would be better to use one pair (brown) for power and the other for voice (blue). It doesn't matter really which, but if you do it as you'd suggested, you would be running a power line next to a signal line, and twisting them together in fact. The twisting is what (to put it simply) prevents this type of interference.

[cowen]

Some configurations of equipment use the blue and brown to provide the POE over the cable and thus splitting the cable can FRY your phones.

[T3Hprogrammer]

This is what I thought at first. But, by splicing in the telephone cable, you disconnect the blue or brown pair from the ethernet connectors at either end. So, connecting a POE device will not harm the telephone board, since the power wouldn't get past the jack (the transmitting pairs have been snipped). Likewise, a POE source, like a switch, would not harm telephones, because the necessary pairs have been cut on that end too. An easy way to think about this is that you're carrying two things in one cable jacket. You could remove the jacket and split apart the telephone pair and the ethernet pairs along the entire cable run, effectively making two cables. They are completely isolated. Two pins on each of the ethernet connectors will be disconnected. I don't recommend doing this, it's just a mental picture to demonstrate how the phone and ethernet will never interfere with each other, except potentially through induced EMF (no pun intended). However, this effect is negligible, especially in the telephone wires. I believe it is negligible in the ethernet wires too, but there is some disagreement to that regard.

[cowen]

EIA/TIA standards and the way some manufactures make their POE equipment will use the BROWN and BLUE pairs in a cable for the POE. So the PAIRS for the Blue would be one side of the power and the Brown would be the other side of the power. Example: DC is not very effective and can require Positive and Negative to run across the blue paired and brown paired cables for efficiency of the POE requirements of the device. This is to get a better conductive path along the cable and prevent over loading conditions. The same can be for the AC versions of the POE devices. it is just not a good idea to split any data cables and to follow established practices and standards of EIA/TIA and the NEC when if come to Power. I have been doing this for 13 years and the failures that come with this are more then the success rates. But I love to diagnose these makes the rent payments every month.

[xsk8er9000]

 This is actually how alot of telco companies do it. They do it to save money. In my eyes this is not a good idea. It limits you to using 10/100mbps which if thats all you need, cool.. But gigabit uses all 8 channels if I remember correctly and also the two signals would give interference two each other so when both the phone and that network connection were active you would get some interference. Obviously there are a lot of variables to this.

[cowen]

Many that do this are splitting a cable that is a Voice cable not a Data cable.

Professionals with integrity would not conceive of this as a permanent design.

[hintss]

actually, it was a data cable designed so it could be voice or data, and he made it both

[cowen]

This configuration would work for 10 meg and inconsistent 100meg The ENTIRE purpose of the 4 pairs is to provide shielding of the cable unto itself. If you run screened twisted pair (STP) as long as the entire run gets grounded the twisted pairs are not so much shielding as the screening is the shield. The WHOLE purpose of the DESIGN behind CAT5, 5Ehanced, CAT6, and DRAFT CAT7 is to provide noise reduction on the cable and balance itself from alien cross talk of nearby cables, motors, ballasts and other noise creating electrical devices. The EIA/TIA standards as well as BICSI are setup that a DATA cable be completely terminated to one jack so that ANY device my use the cable with out regard if it is a House phone, Ethernet signal, Token Ring, or other, Data speeds from 1 meg to 1000 meg are able to transverse a PROPERLY configured EIA/TIA terminated cable.. Standards are introduced in the industry for a reason. We follow these rules so that future expansion is possible when the original home owner dies or moves and the home is turned over to someone else.

[Groxx]

I quite like this setup, though I would miss my gigabit connections for remote backups. And I feel compelled to say that while I like the red/green labeling "for the benefit of the color blind", I must ask... If they're color-blind, how will they tell red/green when actually doing this? (..though while typing that I realized that, if they kept a red light handy, they could tell the red one by the one that gets lighter when lit by red.)

[blackjack929]

 Groxx - you should be ashamed! Treating the disadvantaged as though ONLY the people who see color and color code items!

;-)

We actually can compare shades - and if you put green and red side by side you see a difference in shading. But there is no red or green. And we learn tricks too about using striped wires as guides and just generally in worst case scenarios just make sure the "shades" all line up. Just an FYI from a 20 year vet of the tech-age. You should see me with resistors!

[hintss]

SMD ones have the value printed on. just sayin'

[cowen]

I had a cable tech that was color blind.

He ran circles around the guys that could see colors.

His terminations were better then the non disadvantaged guys.

Now I did not know that he was color blind and once I found out I was truly amazed.

There are a lot of people out there that are handicapped and can overcome the disability and you would never know it.

Personally I try to contract persons with disabilities most of them work better then someone with out a disability.

[pcooper2]

Most men with color blindness are red/green color blind, meaning that they can't distinguish red from green. They can see other colors, though.

[tristantech]

It doesn't matter if your color blind and mix up red and green because they aren't polarity sensitive.

[cowen]

Until you update to digital which is polarity sensitive in most cases.

Manufactures are making Data equipment IDIOT proof so that all that is needed is to run a cable and punch the "wires" down in the slots at both ends with out making sure it is right.

The ports will align themselves to the right pin outs regardless of the (fancy term) Wiremap.

Wiremap is a method to see what wire is to what pin.

Orange pair
Green pair
Data pins

Blue pair
Brown pair
Future use and or grounding for EMI interference.

Structured Cable comes to mind.  The cable in a whole provides the stability and the green and orange are twisted more then the blue and brown pairs are.  Cat6 has even more done with it.  I will not go into a whole explanation of what mathematical science is used to create the cables twisting just know there is.

This basically has to do with magnetism.  These pairs are twisted together in counter twisting rotations. If you have two magnets a North magnet and South magnet they repel each others force.  That is what is going on inside the cable.  That is why the cable has 4 pairs that are lined up the way they are and why each pair is twisted together in better grade cable there is a plastic separator between the pairs(cat6 typically).  Splitting out pairs destroys this entire design.

Running  cables close to EMI (transformers and such is bad too) is reduced by this design but deliberate placement should be used.

The center pins are reserved for line one teleco but it depends on what you are plugging in.  That is where the codes/standards/practices come into place.

EIA/TIA established this years ago (1980s) and we technicians follow these today (2010- and forward) so that one cable can be used with any configuration with out having to tear it up and figure out what the person was thinking that connected the jacks and plugs in the first place.

We follow a strict 568B straight through pattern for a reason.  Specialty cables are heavily marked as such.  The inexperienced just slap it together and hope it works and disclaimer that it if does not they are not responsible for damages.