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can i convert phone wiring in walls to act as only Ethernet network cause 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

so 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 how much the speed will be

thank you in advance

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migrated from serverfault.com Jun 16 '10 at 16:44

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6 Answers 6

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.

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3  
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. –  Scott Lundberg Jun 16 '10 at 15:23
    
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
    
@Scott & BillN: True enough. Thanks. –  joeqwerty Jun 17 '10 at 3:31

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.

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Or replace the phone wiring with Cat5 or better, then you could run PSTN stuff over that, as well as network stuff. –  Tom O'Connor Jun 16 '10 at 14:16

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.

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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).

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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.

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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

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?

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