Networking & Wireless forum


convert telephone cable into ethernet cable

Hi, I have a 5 pair * 0.5mm telephone cable which run through concealed wiring between my master bedroom and my bedroom. 2 wires out of 5 pairs are used for telephone connection so I crimped RJ45 connector to rest of 4 pairs on both sides so that I can connect one end of it in my bedroom router ethernet lan port and second end to the computer in master bedroom. I have a wifi router in my bedroom but it's signal is very week in master bedroom, I had changed a couple or routers but still the same signal strength so i thought the wired solution would be best. I had asked the electrician if he can replace the old 5 pair telephone cable concealed in wall with a ethernet cable, to which he said it will take lot of effort since the cable was concealed long back in the wall and due to multiple cables running through a small concealed wiring pipe it's going to be very difficult to replace the cable and if i still want it then he will have to run a new cable through new concealed pipe which would be time consuming and very expensive too.

So I thought I could simply use the existing 5 pair telephone wire as ethernet cable but after crimping the RJ45 connector and connecting one end to the lan ethernet port on my bedroom router and another end to the computer lan port in the master bedroom, I tried to check the lan connection on the master bedroom computer it doesn't work and it shows no lan connection.

Now in order to check if the wire is properly crimped and there is no breakage in the wire in the wall, i thought of testing it through a different way .i.e. I used a RJ45 to VGA adapter and connected the vga port of my bedroom computer CPU to the monitor in the master bedroom and guess what I was able to view the content played on my bedroom cpu on the master bedroom monitor, this means the cable is working fine to carry a video signal from my bedroom computer to master bedroom computer monitor but somehow it is unable to send the internet signal from one end to another end. I believe i can use some converter on both ends which could resolve this issue. Can you please advise if there is any converter in the market which could help resolve this problem.

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All Answers

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Sorry. No.

In reply to: convert telephone cable into ethernet cable

Physics says no. Why? Twisted pair Ethernet has those twists for a specific reason so while you could wire what you have to Ethernet jacks it isn't the right cable for the job due to the lack of twists and pairs.

I'm not saying you can't electrically wire it up, I'm writing it would have issues at Ethernet speeds.
There is no need for any adapter or convertor. Just RJ45 ends and the crimper. And there are now no-crimp RJ45 ends. Example:

Let's cover the other way to connect when there is no cable. PowerLine Ethernet. I always liked this one as it does it all. Picture follows:

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Telephone cable to ethernet cable

In reply to: Sorry. No.

As mentioned in my initial thread, I have already crimped the 4 pairs out of the 5 pairs with RJ45 connectors on both end and the wire is able to transfer the video signal through it from one bedroom to another bedroom with the RJ45 to VGA converter/adapter., so I was just thinking if we can use some sort of converter to transfer the internet signal through the wire.

Wire Image

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In reply to: Telephone cable to ethernet cable

No converter is required. The phone may not be twisted in pairs and electrically correct will fail when it's time to transfer at 10 and 100 megabit speeds. The video might work since it's one way and we don't care about crosstalk.

Just in case you do have pairs, the pairs SHALL go to specific pins. Or the cable will fail even if electrically correct. This has upset many folk that try to wire it themselves, they don't get the pairs right and they ring it out and electrically it passes, but does not work.

Which wire pairs to what pins is on the web such as

For a 2 wire pair cable you would be using pins 1 and 2 then 3 and 6. I've had folk argue with me over this so I will state, I didn't make the rules.

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crimping order

In reply to: Nope.

ok. I have used T-568B order on both ends. is that a problem ?

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Only if it doesn't work.

In reply to: crimping order

There are reasons why phone lines can't be used for Ethernet. We've covered those short of a classes in Electronics.

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