Can I convert phone wiring in walls to act as only Ethernet network because the phone wiring is not in use and not connected to the phone company so there is no voltage in the wires

I remove the wall plate and I find 6 wires blue,blue/white,green,green/white,orange,orange/white , and I know that Ethernet use 8

Here is what I am thinking. Get Ethernet cable cut it in half and attach wires from wall to the first computer and the same with the other computer

If this is possible do I just attach wires in the same color and ignore brown wire or do I have to rearrange wires , and what will the speed will be

12 Answers 12


Hmm... I thought that I posted an answer earlier but maybe I didn't. Anyhoo, CAT3 cable will support 10mbps Ethernet (10BASE-T) but not FastEthernet (100BASE-TX) so it should be possible to use it for Ethernet if there are enough pairs and if the connectors are terminated correctly. It doesn't matter which wires you use as long as you use the same colors on both sides of the "run" and terminate the connectors correctly.

  • 4
    Joe: even though it's cat3, it's still twisted, so it does matter which wires you use. You would want one pair for pins 1 & 2 and another pair for 3 & 6. If you don't, the cross talk will prevent even 10MB from working. Jun 16 '10 at 15:23
  • 2
    Generally on phone cable, you'll have Red/Green twisted, and Yellow/Black Twisted. My guess is the other pair in the OP's scenario will also be twisted. If I HAD to make this work, I'd probably use R/G as 1&2 and Y/B as 3&6 to eliminate crosstalk as Scott suggested.
    – BillN
    Jun 16 '10 at 15:55

Options for bandwidths higher than 10 Mbit/s

Other answers here explore the possibility to use the Cat3 phone cabling for 10 Mbit/s (10BASE-T) Ethernet only.

There are ways to use Cat3 phone cables at higher speeds, as listed below. They do not run Ethernet over the cable but protocols more adapted to the phone cable medium, but all provide Ethernet at the connector sockets used to access these connections. So for practical purposes, it does not matter that it's not Ethernet.

(1) G.hn over twisted pair

G.hn is a standard for home networking over legacy cabling (phone cables, coax and power lines). So, exactly made for the purpose at hand. It provides up to 2 Gbit/s, with commercial devices for phone lines typically providing 1 Gbit/s. That's the PHY layer signalling rate though, while the usable data rate on the IP layer would be 400 Mbit/s (source). The transmission distance is up to 1000 m.

One nice attribute of G.hn is that it's not limited to point-to-point connections like VDSL modems are. This makes it more adapted to phone cabling, which usually branches into several wall sockets in the different rooms. See the cabling example for the Solwise E100M.

A disadvantage of G.hn compared to VDSL / VDSL2 is that only one pair in a multi-core cable can be used for it (source), so link aggregation requires multiple cables.

Available products (not exhaustive):

(2) VDSL P2P modems

Available products (not exhaustive):

  • StarTech.com 110VDSLEXT. A pair of VDSL2 modems for point-to-point connections up to 100 Mbit/s (at short distance) resp. 10 Mbit/s (at the 1 km maximum). They specifically mention that a single Cat5 cable can contain up to four of these connections, allowing to multiply the speed by link aggregation. Ca. 280 USD for a pair (see).

  • Blackbox Ethernet Extender Kit. Seems to be based on VDSL, but they don't tell. Provides up to 168 Mbit/s, and can cover longer ranges (4 Mbit/s at 3 km). 640 USD for a pair of two.

  • Panoptic Technology IntraLAN VDSL2 P2P Modem. Said to provide 100 Mbit/s up to 300 m, down to 20 Mbit/s at 1.7 km. They also offer a concentrator as a central unit that allows to use these devices comfortably for distribution in larger compounds. No prices / purchase options found.

(3) HomePNA

HomePNA was a competing standard to G.hn, but their standards group merged in 2013 with the HomeGrid forum behind their G.hn standard (source). So HomePNA is considered legacy now. There have been 40 million HomePNA devices in operation though (source), so it will still be possible to get them used. See the list of HomePNA products.


As someone who is doing this currently, I can say that it does work. As Scott pointed out, you only actually use 2 of the pairs for standard ethernet. (the other pairs are used for Power over Ethernet though).

You will obviously get better performance from Cat5, but your landlord might have something to say about ripping out the current wiring. Over a short distance, you might even get 100Mb out of it.

I will give you one note of warning. With the old wiring in my house, the phone company had looped the same strands through multiple phone jacks and tapped into the middle of the strands. Make sure that you are putting jacks on the ends of unbroken strands, and that there arent other jacks or splices in the middle somewhere.

  • 3
    Gigabit Ethernet uses all 4 pair, it does not use 2 pair as 10 and 100 Mb did.
    – Chris S
    Jun 18 '10 at 3:02
  • Depends on the cable used, and the distance ... I was lucky, got as well 100MBit/s out of my phone cable, See my answer for a details
    – Alex
    Mar 4 '20 at 21:54

Tut Systems sells baluns that can be used to use phone wire for low-speed ethernet, however, using wifi is going to give better performance. You could use VDSL adaptors, but, the cost of those for the short range 100mb/sec is going to exceed the cost of getting 802.11n adaptors and a gateway. Getting anything above 100mb/sec over those wires is going to be almost impossible.

  • "VDSL adapters" would here refer to special VDSL peer-to-peer modems (example), not the usual VDSL adapter for Internet uplink.
    – tanius
    Oct 5 '18 at 22:46

No. Phone wire is Cat3, it's quality is much too low to support modern Ethernet (which requires Cat5 or higher).

HPNA adapters can use phone lines to tranmit 802.3 frames; but WiFi would be much cheaper.

  • 1
    Or replace the phone wiring with Cat5 or better, then you could run PSTN stuff over that, as well as network stuff. Jun 16 '10 at 14:16
  • Well HomePlug systems can turn your mains wiring into an ethernet transport so why not a phone line? In fact, SolWise used to sell Powerline for phone-line products.
    – Mr. Boy
    Apr 27 '17 at 16:40
  • Also how does your internet get into your router except through the phone socket (in the UK)?
    – Mr. Boy
    Apr 27 '17 at 16:54
  • 1
    10BaesT was designed to work with Cat3, but requires a straight shot from terminal to switch rather than the spiced and branched mess that normal house telephone lines are.
    – psusi
    Feb 19 '18 at 22:33
  • @Mr.Boy fibre optic & cable aren't that uncommon at least in built up areas.
    – Lex
    Jul 23 '18 at 21:51

Yes, you can have 10Mbit/s etherhet and for that you only need 2 pares (4wires).

I have actually done this in the past, and 10baseT was design to work on phone lines.

But if you would like higher speeds.... newer cables.

So put some connectors on the cable, and give it a go. Maybe the speed is good enough?

  • Unless the lines are spliced and branched all over the house as is typical for home telephone wiring. Ethernet needs a straight shot from terminal to switch.
    – psusi
    Feb 19 '18 at 22:32
  • I was lucky and got 100MBit/s out of my old phone cables. Depends on the distance, and the exact cable type ... for sure worth a try.
    – Alex
    Mar 4 '20 at 21:56

Plain old telephone cable (two twisted pairs) is good for 10Mbit Ethernet for runs of 10..20 metres. Your switch will automaticall fall down to 10Mbit if the quality of the transmission is not suitable for higher speeds.

  • As an aside: I think that in The Netherlands such old cables are not twisted (or have a very low number of twists per some long unit of length, which I doubt will help in cancelling out interference). But things might be different in other countries.
    – Arjan
    Sep 16 '14 at 20:07
  • Unless the lines are spliced and branched all over the house as is typical for home telephone wiring. Ethernet needs a straight shot from terminal to switch.
    – psusi
    Feb 19 '18 at 22:32
  • I did this a few years ago but found that the router recognized it (wrongly) as 100 Mbit/s Ethernet, resulting in a very unreliable connection. I forced it to see it as 10 Mbit/s Ethernet by putting one small legacy 10BASE-T switch in between.
    – tanius
    Oct 5 '18 at 21:58

Solwise sell this product: https://www.solwise.co.uk/net-ghn-tp-e1000m.html

The Solwise E100M transfers network data through the existing phone lines at the rate of up to 1000Mbps and a distance of up to a maximum 1000m. It is ideal for use in small offices, factories, mines, elevator improvements, hotels and schools, providing a high performance resolution to project businesses and system integrators. It can solve the problems of long distance data transmission, network monitoring and data collection etc.

It is a bit pricey but suggests it is possible.

  • Great find. Not Ethernet though but G.hn technology. The device converts to Ethernet, so practically equivalent. It seems possible to connect one such device next to each phone socket in a branched phone cabling typical for a house, and even to use the phones in parallel (source).
    – tanius
    Oct 5 '18 at 22:19
  • Before buying extra hardware which will cost extra money and eat extra power, it should be chekced if the current cabling is sufficient .. 100MBit/s are possible for some cable types.
    – Alex
    Mar 4 '20 at 21:47

According to Wikipedia you can only get 10MBit/s or some special 100BASE-T4 if it is a Cat3 cable, which mostly was used in US.

I have a J-Y(ST)Y installation in my house (germany). I use it for ethernet and get 100MBit/s out of it (effectively measured 93MBit/s) For my 50MBit/s internet-connection, that's more than suficient. Though the speed will depend on the length of your cable.

My suggestion would be: Just take a try!

Note that most telephone cables are slightly drilled in pairs. It is important to always catch the right pairs. Here how I connected my cables:

1-2 red-blue
3-6 white yellow
5-4 white green
7-8 white brown

Be sure to connect them in the same way on both sides. I used some cat6e wall socket and a patchpanel on the opposite site.

It even seems to be sufficient to only connect the first 4 wires.


Like they said, no. If you truly do not need it in a couple of rooms though... you can always use the phone cable as pull cable for your cat 5 (crimp the ends on after the pull).

  • Thats a lie, it is possible. I got 100MBit/s out of my phone cable. On a concealed installation you will not be able to pull anything
    – Alex
    Mar 4 '20 at 21:49

It seems to me that the above info that phone lines will only give 10Mbps is false. AT&T came into my house to upgrade my Uverse internet from 6Mbps to 45Mbps (ATT had to change out the ATT router/modem), I let the technician know that one room in my house has a terrible wifi connection, he gave some solutions of buying an adapter to turn my phone wiring into an Ethernet cable. However, he also said that another phone jack of mine, in a different room, could be turned into an Ethernet cable - He said that he could not convert my other phone jacks to Ethernet, because only this one was connected to the uverse service (years earlier ATT used this jack to give me uverse phone service - later I cancelled this service) - So I'm not sure if this means that this particular phone cable is terminating inside the phone box outside my house or if this phone cable runs outside and then comes back into my house where all the other att cables (uverse & direct tv) come back into the house and plug into my uverse router/modem. Regardless of how this one phone cable is terminated, the only thing that the att tech changed in my upstairs bedroom was the RJ11 jack was changed to a RJ45 jack. My computer that plugs into this new Ethernet jack, when I run a speed test, is consistently getting 47Mbps. So not sure why everyone is saying that you can only get 10Mbps over a phone line. The ATT tech, neither years ago when this one jack was configured to carry att voip service, nor when the att tech recently came to change out the att router/modem, did either att tech change out the phone cabling with Ethernet cabling, this is just regular phone cabling.

  • 1
    I just read another commenter on a different page that his house was built in 2004 (which is the same year that my house was built) and that his is wired with cat5....So I'm guessing that I'm getting 47Mbps, because my house was originally built with cat5 cabling
    – user727339
    Aug 4 '17 at 16:10

Why not just use poweline? They are cheap and effective - I’ve 3, two with Wi-fi and one just a cable connector.

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