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Rewiring a new ADSL cable

  • IT

One of the problems I’ve had since moving house, is that my Internet services (currently provided by BT) were installed in the living room of the house I’m in. The master socket / street wiring were replaced to my house, and the only way I could get internet was using a Wireless USB dongle on my PC and then connecting to the internet through WiFI on my home computer. As my equipment was downstairs.

Whilst this functions and works fine as is, I’ve never liked this arrangement

My preference has always been for hardwired internet, and I wanted to change that. I previously had an extension wired in so the cabling was already there I just needed to replace it. I decided that by rewiring a new ADSL cable in my household I could extend it from the Master socket into my rear bedroom. BT’s preference isn’t to do this, as they like the runs to be as short as possible

The benefits I could see of going wired over wireless were suitable to me. I could get faster speeds because the WiFi was unreliable as it was based on signal performance, the network was at risk of Wifi attacks, and I could use my networking equipment. This was the main benefit. I have a 24-port Cisco Catalyst switch which I use for networking my devices, and without a network connection I lose all my networking. I didn’t want to route a LAN cable as they’re bulky so chose this option instead.

In order to do this, I determined the best course of action was simply buying my own cables and using RJ11 connectors and making it myself.

There is plenty of argument to suggest you should run the shortest cable possible and any extension cables used can result in poor performance when it comes to internet to the point where it’s unusable. So BT are always saying you shouldn’t do this. It’s always suggested that the signal performance wlll be so low you will have reliability issues, suffer massive performance drops and so forth.

To be realistic however, we’re talking an extra 10 Metres of cable length that I added over the one provided with the kits. The cable has already travelled several miles from the nearest exchange to juction box, so a few extra metres won’t make that much difference in terms of performance.

I knew I wanted two things in order to do this job. I’d need some internal phone cable. I wanted to use the proper BT spec cable so I purchased some CW1308 cable from Toolstation  (made by Doncaster Cables), and some RJ11 connectors from Amazon. I believe ADSL cable only uses 2 wires (1 pair) anyway, so it should be fine for the connection. In hindsight I would have purchased the crimp through RJ11 cables if I could find them as it would have made wiring lots easier and faster for me.

I wasn’t 100% sure about the colours I used, so I did a quick search online, and modified it from the Techwalla article, Instead of using an RJ45 to RJ11 arrangement, I just did an RJ11 to RJ11 setup.

The cables were crimped in the following order – White/Orange, Blue/White, White/Blue, Orange/White on both ends of the cable. As a note to this, the pins are based on the crimp “shoulder” (the little bit that clicks and locks it into place) facing down not upwards. So you’re working from Left to Right.

After I made up the cable (to the length I thought I’d require), I took it downstairs and hooked it up, a couple of minutes later my internet connected without problems, I did a speed test and performance was acceptable. So I went about replacing it. I did this test first, because it was pointless replacing the cable and doing all the work if it wouldn’t have worked or the performance suffered. It just meant I used an RJ11 connector extra, and for the 5 mins of testing it could have potentially saved me 2 hours work.

Anyway, my basic test worked, so I continued with the project

How I made my own ADSL cable and rewired it

Below are the following steps on how I managed to rewire the adsl cable in my household.

  • Purchased BT-spec CW1308 cable from Toolstation for £22.56
  • Purchased RJ11 connectors from Amazon for £1.89, in hindsight I would have bought RJ11 pass through if I could find them
  • Measure up the cable required (I guesstimated this step with my arms on the route) then added “extra” for safety. Turns out my guesses were correct, I had about 2 metres extra at the end. I still have about 80m of cable in the drum, so I could afford to be plentiful with the extra wire. Easier to have too much than not enough.
  • Tape the end of the new cable to the old one
  • Lifting carpet, pull up the old cable, and use the old cable to “pull” the new cable (watch out for old staples, I managed to cut my leg)
  • Routed around the house, I then used some network crimpers to strip the wires
  • I use the cotton cord to pull it down (this is done incase you’ve damaged wires) by accident and expose fresh wire
  • Arranged the cables in this order  (White/Orange, Blue/White, White/Blue, Orange/White) with the locking tab facing down. You can straighten the cable with a pen or pencil
  • Crimped the connectors and rerouted equipment


Final Speed results

For reference BT’s equipment looks like I’m on a profile of 40Mb/s down and 6Mb/s up

BT maximum line speeds

I never actually tested the speeds using a LAN cable with the old ADSL cable, when I was using WiFi I was getting around 27 MB/s in my bedroom, so wasn’t really bothered. As it was still faster.

For reference these were the WiFI speeds using my cable and OEM adsl cable from my phone in the living room

CableLength (APPROX)PingUpstreamDownstream
Factory 3m22ms27.736.25
New cable13m19ms26.885.57

As you can see, there was a slight difference in speed over WiFI between the two cables, but this can also vary at the time of day you’re testing and when it was used. There was about 3% loss in download, and 10% loss in upload. Realistically I’m never going to notice this type of loss anyway which is why I’m not bothered. I just wanted to show this for reference

The speed results with my new ADSL cable

It’s now been around 24 hours since I fitted the new cable and used it, normally taking around 1 week to update to the correct speeds. I wanted to post the results however from some sites. These are the final results, it appears I have 35 Mb/s downspeed and 6 Mb/s up speed, so I’m happy with these results because they’re faster than what I had before. They’re also roughly the speeds I was expecting as when I used to live at this address I had around 37Mb/s down and 5Mb/s up.

35.72 Mb/s Downstream 6.13 Mb/s Upstream 16ms ping 1.25ms jitter

35.70 Mb/s Downstream 5.82 Mb/s Upstream 13ms ping

35.33 Mb/s Downstream 6.40 Mb/s Upstream 16ms ping

The legalities of doing this

Whilst I’m not a legal professional, so do this at your own risk, there are none. Basically BT own the master socket, and are responsible for the line going into the back of the master socket. After this any additional wiring is the responsibility of the home owner, and it’s up to them to wire it. When wiring in your own phone lines etc, you are meant to do it from the rear of the removable faceplate as the removable faceplate portion is “your” side of the equipment. If you break the equipment, you’re responsible for paying for the repairs.

This is why you’re allowed to remove the removable faceplate and use the “test” socket behind, because the test socket is actually where BT have the cable wired to. So if your internet works with this it’s the front portion which is your side, if it doesn’t work with the test socket. Then that means the problem is with the line.

My existing master socket (v4) has a faceplate, I never looked fully but I’m sure it’s still removable. I didn’t want to interfere with this for legalities, and to make it simpler to prove I haven’t touched anything that could affect their setup. So my method is what works for me. Basically all I’m doing is making a longer cable, there’s no difference to BT providing you a longer cable. So feel free to do this yourself.

I could have potentially wired the socket RJ11 plugs wrong, but that would have shown up later on, or from further research. Looking at this diagram I wired it up correctly anyway. My relevant column is the “colors” one because I wasn’t using Cat5 cable, just a two pair cable. Realistically I only needed to wire up 1 pair as that’s all that is used, I just wanted to wire up the others for crimping purposes. Technically I could have cut them to prevent interference, but I’m happy without. I may do this at a later date if I find it causing problems.

Final thoughts on rewiring my adsl cable

The primary purpose was for my networking at home however. I’m one of those people who have a preference to a hardwired network, as opposed to wireless. As this type of network is more secured and reliable. Signals can degrade fast with wireless. With the right cables, wired can run for hundreds of metres and handle more bandwidth / data.