United Kingdom internal phone systems




This guide was originally created to show users how to replace and re-wire the user side internal telephone cabling with Category5e/6 cable in an attempt to reduce interference that could hinder broadband services like xDSL.

However is now updated with other tips and tricks to improve line stats further.










Front Cover.................................................................................. 1

Contents Page.............................................................................. 2

Introduction................................................................................. 3

The Rules..................................................................................... 4

Cable Education.......................................................................... 5

Tools and Items Needed.............................................................. 6

Getting Started............................................................................. 7

Extension Wiring...................................................................... 22

Ring what?................................................................................. 30

Help with Extension Wiring.................................................... 39

Other interesting stuff/notes..................................................... 41

Bibliography.............................................................................. 42






Hi, the first thing a lot of people will be wondering is why!?! The answer is simple. With rate adaptive services becoming common in the UK, people want the fastest line speed possible for their money. With nearly all Internet Service Providers currently charging customers the same price for a line that can get the full 8mb/s, as a line that can support speeds only up to 3mb/s or even 288kb/s, it would seem wise to attempt to achieve the higher speed as you would receive better value for money.


So… having more speed for your money is a good incentive! But there are other factors that can play into it. RF Interference - Electro Magnetic Interference (EMI) from devices as simple as an AM radio can interfere with xDSL signals and this can be very annoying, and can result in slower connection speeds, and even connection drops. Some other examples of devices can be an old TV (or even a neighbours’ TV next door), a radio, lighting (some Christmas lights can be especially bad). Here is a memo that BT passed to ISP’s;

It has come to BT's attention that an extremely small percentage of seasonal lighting, which can be used both internally and externally, may cause interference with the broadband service. When the lighting control unit is set to any mode other than a steady state it may generate high levels of radio frequency noise and may cause the broadband service to lose synchronization.”

Other reasons could be that the carpet installers nailed and stabled though your phone line, which can not only slows your rate adaptive xDSL service down or make’s it inoperable but it can also interfere with your POTS (Plain old telephone service).

Another reason for rewiring with cat5e/6 is that a lot of users will have poor quality telephone cable such as none twisted pair ALARM cable, this cable just wasn’t designed to carry xDSL signals and should be replaced if it’s causing a fault or hindering performance.


So you now want to learn how? Well first there are some rules. But before the rules I must just point out that I am going to add material from other sources (all listed throughout and at the end of this document), along with notes, comment’s and pictures from myself. If things seem repetitive, don’t worry it’s simply because I want you to understand it fully and not make a total cock-up of it all.


The task is very simple, just read the WHOLE guide before starting with anything, and make sure you understand it all, especially the rules…


The Rules and Main points


Just before the rules there is one main point, if it’s not broke, then don’t fix it! As it is probably not worthwhile replacing good quality twisted pair telephone cable, that is in a good condition and well terminated, replacing cable in that state with cat5e/6 can show very little or no improvement.

If you know how to get your line-stats from your modem/router then do so, then if an NTE5 Master Socket (covered later in this guide) is fitted, take the line-stats from test socket and compare. If a big improvement is seen, due to the poor extension cabling etc, then rewiring could be a good decision to make.


1) If you do not know what you’re doing; pay a professional to do it.


2) You must NOT replace or move any of BT’s property; this includes but is not limited to the following;

  • The Drop cable – The cable that come’s from outside to the inside.
  • A junction box – If it is before the BT master socket.
  • Cable before the BT master socket.
  • Cable after the BT master socket (if BT holds ownership).


The Master line box is the "demarcation" point between your telephone equipment, wiring and BT's Exchange Line.

The reason this is so, is that everything on your side of the master, is your problem. Everything on BT's side, including the Master line box itself, is BT's problem. It needs to stay this way!

Now if you want to something along the lines of; move the Master socket (to get rid of the crap wire between that junction box and master socket) or to relocate the Master socket to where the drop cable enters your premises, then to do this is YOUR choice, if you mess it up, then you will need BT to sort it out, IF they sort it out for you that is (keep reading).

If you successfully move your Master socket to have more “high quality user-side wiring” then good for you, but it is ILLEGAL to do this, if it is clear and obvious that you moved it yourself and BT issue’s a fine and/or terminate your line. Don’t say you weren't warned.

That was the warning… just in case you didn’t understand the ILLEGAL part.


3) When inserting wires into IDC terminals, use the correct tool! DO NOT use a flat blade headed screw driver, as this pushes the blades apart and doesn’t make a good connection in the wire (if it makes a connection at all!).

The whole point of this exercise is to upgrade your normal or damaged cable to high quality cable, but badly terminated connections (by not using the correct tools!) can make it worse that just using rubbish cable.

So when wiring to IDC terminal’s please use the correct tool, as IDC tools can be found as cheap as 49p!


4) Your new Category 5e/6 cable must be SOLID core cable. Most cable you buy over 10meters is usually solid core, but check! This is very important because the IDC connectors are not designed to terminate STRANDED core cable.


5) Rule 5 – this rule is an easy one, and it’s to ensure you read every word in this guide.

You must understand it all, before doing ANYTHING!

If you find yourself breaking this rule in anyway, then you MUST follow rule 1. J

Cable Education


The list below shows the current versions of category cable


Cat 1: Currently unrecognized by TIA/EIA. Previously used for POTS telephone communications, ISDN and doorbell wiring.

Cat 2: Currently unrecognized by TIA/EIA. Previously was frequently used on 4Mbit/s token ring networks.

Cat 3: Current cable standard, used for data networks utilizing frequencies up to 16MHz. Popular for 10 Mbit/s Ethernet networks.

Cat 4: Currently unrecognized by TIA/EIA. Provided performance of up to 20MHz, and was frequently used on 16Mbit/s token ring networks.

Cat 5: Currently unrecognized by TIA/EIA. Provided performance of up to 100MHz, and was frequently used on 100Mbit/s Ethernet networks. Suitable for 1000BASE-T gigabit Ethernet.

Cat 5e: Provides performance of up to 125MHz, and is frequently used for 1000BASE-T gigabit Ethernet.

Cat 6: Defined by the ANSI TIA/EIA 568B-2.1. It provides performance of up to 250MHz, more than double category 5 and 5e.


As you can see CAT5e cable supports frequencies up to 125MHz and with ADSL running at up to 1.1MHz, ADSL2+ at up to 2.2MHz and VDSL2 into double figures.


So using CAT5e/6 for your extensions defiantly means it will be stable, and due to the high quality of the cable, interference at the lower frequencies will be reduced, as all category cable is backward compatible.


















Above shows the colour of the pairs found in CAT5e/6 cable, and lists the number of the pair.


Below shows a picture of some gray solid core CAT5e cable with the outer sheath removed to show the twisted pairs.


Tools and items needed


Items needed are going to be tools/equipment, time, and of course… cable.


  • A flat headed electricians’ screw driver.
  • A small cross headed Phillips screw driver.
  • A “Krone-type" IDC (Insulation displacement connector) Punch-Down insertion tool. This can be a cheap plastic one (the blade wears out after about 6 insertions so try get one for every socket) or the better metal one (it lasts!) The correct tool can also come with a hook for removing wires from existing IDC terminals, and a flat headed screw driver for unscrewing the socket plates.
    It can be purchased at http://www.clarity.it/acatalog/punchdown_tools.html or in B&Q.
  • Catagory5e/6 network cable, this must be solid-core cable, not stranded or it will not connect/terminate correctly to the IDC terminals. Up to 30metres of PLAIN WHITE! can be purchased from
    however Belkin also sell up to 30metres of white Cat5e cable (but has writing down one side) this is slightly cheaper, you just cut the plugs off, and make sure the writing is facing the wall/or cable under the carpet. It can be purchased from places like
    http://www.ebuyer.co.uk/ and many more places, the cable colour can be whatever you like, but it must be solid core cable not stranded.
  • Found a place to get a huge amount of Cat5e cheap, 305meters of it, in white,


  • A hammer – to secure your cable with cable clips.
  • Cable cleats/clips – these should be 5mm for Cat5e and I think 6mm for cat6 and can be purchased from many places, B&Q, even at http://www.clarity.it/acatalog/adsl_extensions.html
  • Wire cutters – to cut the cable at desired lengths, to remove the outer sheath of the cable, and to trim the end of the cable once inserted into the IDC terminals if disposable IDC tools are used.
  • Wire stripers – to strip some sheath from wire when wiring a custom NTE5 line-box.
  • Pen/Paper - to make notes and stuff, if you need too.


Of course you can purchase any of your items from the place of your choice.

Getting Started


When in possession of all your tools and have the amount cable needed, your first thing is to make a map of your current wiring setup; this is done to just help you know what you’re replacing. Doing this can also help you understand rule2 (see above) make sure you know what is yours to replace, and what is BT’s. Please make sure you read this entire guide before starting, as you do not want to get halfway thru and then end up getting stuck.


Next I am just going to go through some basic socket education.


No matter what type of socket you have, they are very simple to understand.


This table shows the main types of sockets you should find in your premises.

If it is different, try do a little bit of research before starting.

“LJU = Line Jack Unit”



 Dimensions: 55 mm x 55 mm x 25 mm


Master IDC Socket, with a capacitor, resistor and surge arrestor.


Secondary (extension) IDC socket without any components fitted.


Master screw terminal version of LJU1/1A.


Secondary screw terminal version of LJU1/3A



 Dimensions: 68 mm x 68 mm x 25 mm


Master IDC Socket, with a capacitor, resistor and surge arrestor.


PABX Master IDC Socket, with a capacitor, but no resistor or surge arrestor.


Secondary (extension) IDC socket without any components fitted.


Secondary (extension) IDC Socket is as a 3A but with reverse configuration (left latching), designed to accept 430/630 plugs rather than the normal 431/631 plugs.


Master screw terminal version of LJU2/1A.


PABX Master screw terminal version of LJU2/2A.


Secondary screw terminal version of LJU2/3A


Master for a table top payphone (contains an earth connection for lightning protector)



 Dimensions: 85 mm x 85 mm


Master IDC Socket, with a capacitor, resistor and surge arrestor.


PABX Master IDC Socket, with a capacitor, but no resistor or surge arrestor.


Secondary (extension) IDC socket without any components fitted.


Secondary (extension) IDC Socket is as a 3A but with reverse configuration (left latching), designed to accept 430/630 plugs rather than the normal 431/631 plugs.


Master screw terminal version of LJU3/1A.


PABX Master screw terminal version of LJU3/2A.


Secondary screw terminal version of LJU3/3A

The main difference upon looking at an LJU style line-box is the size of the unit; all can be different in terms of how they are mounted to the wall. Most users will have an LJU style master / or an NTE5 master and an LJU slave (secondary extension), that is, if any extensions are installed.


Of course if you do not have any extensions then you have no user-side wiring to replace, as the only wire you as the end-user are allowed to replace is the cabling after the Master socket, have a look up at Rule-2. As you may have guessed you can learn a lot from this guide, but you have already been warned if you are attempting to do something along the lines of; Relocate the Master nearer to the drop-cable (where BT’s cable enters the premise), and then using cable such as Cat5e/Cat6 to a new extension (where your Master Socket was originally situated)

Again I will point out you are NOT allowed to do this; as it would breach your contract with BT, just contact BT and get them do it, simply ask for a Master Socket relocate.


If you’re looking to install your own extensions, then this guide does cover how to do this (but not the DIY side of it), if you are looking to use Category5e/6 cable then you’re a wise person. J

Take a look at all the pictures of the front and back of the sockets, familiarise yourself with them and your own equipment.


This guide will show you how to wire your extensions from an NTE5 type master socket using Cat5e/6 cable. If you have LJU type master socket and wish to use an NTE5 ADSL face plate, you are not out of luck! The NTE5 can be installed legally by the user.

(Or contact BT and they will fit one for around £30)


This guide shows how to wire the extensions in IDC terminals not the Screw types.

Extra Note: If you have an LJU style Master line-box, they are exactly the same as the LJU extension sockets apart from the extension sockets do not have components inside,

So wiring to them is practically the same as wiring to NTE faceplate or extensions.


Now nearly every BT Master line-box installed since around the 1980's has been this kind.

As you can see, the lower half is separate in three sections. The rear section on this picture is the surface mount "back-plate" however this could be embedded in the wall as a flush mount. The top front section is the front, this holds the master components.

The separate lower front panel is the "face-plate” / “front-plate".

So if your BT master socket isn't this type, then devices like ADSL-Nation’s superb XTE faceplate adaptor and BT’s NTE5 ADSL adaptor faceplate are of NO USE to you, as they replace the lower front half of the NTE5 unit, with a face-plate that contains the filter components.

If you wish to use an ADSL-faceplate then you just wire one up as normal, depending on what kind of extension setup you want, (this is explained in the included instructions)

If you would like to acquire and fit your own NTE5 line box, you can still legally do so.

As long as your not breaking Rule-2 by replacing the current BT Master Socket with your own custom NTE5.
Many places sell NTE5 units.


Austin Taylor sells NTE5’s.

Get to http://www.austin-taylor.co.uk/pages/nte5.htm


Clarity.it sells NTE5's.

Get to http://www.clarity.it/acatalog/lineboxes.html

Solwise.co.uk sells NTE5’s, other items and tools.

Get to http://www.solwise.co.uk/telesun.htm


Many more places will sell or resell the NTE5 Master Line Box, but again these are not BT Master Sockets, and as said, should not be used to completely replace the BT Line box.

I will cover this fact in more detail below; this is a side note about the rear of the NTE5 and its faceplate.


Below shows a picture of the same NTE5 shown above found on Google Image search, this time it shows the rear of the NTE5 Socket.


Rear view of NTE5

For more pictures, read my section on wiring the NTE5, but take notice that on the NTE5 above, you can see six terminals on the face plate.


Some may have 1-6, some have 2-5 (as 1 and 6 do not do anything anyway, and ADSL faceplates usually come with 2-5 and AB (not the BT AB connectors) the AB connectors on the ADSL faceplates are used for extensions as terminals 2 and 5 are, they are for if you choose to have ADSL and VOICE or just VOICE services on your extensions or not.


When using an ADSL faceplate, I will point out that when using the AB connectors for extensions instead of 2 and 5 connectors, the wire you would place in 2 connects to B, and the wire you connect to 5, connects to A.


You must not completely replace the BT master socket with a custom NTE5 unit, as rule-2 says. Replacing your BT Master Socket with a custom NTE5 is a breach of BT regulations and is illegal, and you could face consequences as described in rule-2.

How will BT tell? Well for starters only the BT installed NTE5's have the little BT logo in the top left of the unit, the logo can be a T in a circle with two dots at the right section of the T the T logo can appear in the top right of the unit, or more recently the BT Piper logo (as shown on the NTE5 I use in the wiring section).



Note: the built in BT logo in the top left corner. (As said this can be a T in a circle also)



If you are without a BT NTE5 style Master Line Box, and unable to use the BT ADSL faceplate, or ADSL-Nations XTE2005 ADSL face-plate instead of micro-filters, then here is how to add your own custom NTE5 as purchased from any the places listed above.

Again; RULE-2!

All you have to do is install your custom NTE5 master socket as the very first extension off the BT Master socket, and then install your extension sockets from your custom NTE5.

Basically, you have your BT Master socket, going to your custom NTE5, going to your extensions. Simple!

Below is a simple drawing I made in MS-Paint of what I just said above;

The diagram should be self-explanatory as it shows what colours go where. If you do not understand that diagram then you are breaking Rule-5 and should follow Rule-1, then you get a BT NTE5 anyway which replaces the LJU style, and then there is no fuss at all.


I do actually recommend spending the small amount to get BT to replace your old style master socket with an NTE5 master socket, as it just makes things a lot simpler.


The exchange line connection points on the rear of the NTE5 unit, are two screw plate terminals marked A and B (as shown how to wire later on). Connect extension wires 2 & 5 (Blue and White/Blue) from the BT Master to these terminals, and you now have a working NTE5 Master Socket. Now you can fit an ADSL face plate and/or wire your extensions.

All you are doing is pretending the custom NTE5 is really your real master socket.

As said in Rule-2 an existing extension cable running from a non-NTE5 master socket to an extension socket, might also be BT property and technically you should not move or replace it.

If a BT engineer ever comes round, and you've replaced your BT master socket illegally with a non-BT master socket then he/she is likely to issue one of the two consequences I mentioned in Rule-2, but they probably would not be bothered about the extension cabling. So if you're not sure about the ownership of an existing extension and the cable after the master socket, then you should come get BT to remove it, like before if BT come round they will probably install an NTE5 anyway, so then no need for the custom NTE5. The choice, as always, is yours.


Now if you do not have any extensions and you are installing extensions from the LJU style master box you will need to know how the cabling works on the back of it.




Drop Cable.

Master Socket  

1st Secondary Socket

2nd Secondary Socket



Not used







'B' wire (-50V to earth)







Bell wire







Earth (PABX use only)







'A' wire (0V to earth) 







Not used







The above shows how the drop cable wires go to pins 2 and 5, (these you should not touch)


Note: The incoming cable wires before the master socket could be any colour, not just Orange or White, if it's a second line then they might be a Green or Black pair, or even Red/Slate, or Blue/Brown, maybe the incomer is not drop wire at all, so might be Blue –White/Blue or Red - Blue on even older cables, but you shouldn’t be touching them anyway!

If wiring from an LJU style master, you can wire up to the LJU extensions using those colour codes as shown in the table above.


(When using Cat5e/6) you have 4 twisted pairs (8wires)

















Four pairs, 8 wires, 4 coloured, 4 white with colours mixed on.



On your phone cable you usually will have BLUE/WHITE and WHITE/BLUE, this means when BLUE comes first, it is mainly BLUE with WHITE splodges, and visa-versa.


On Cat5e/Cat6 the First colour is usually solid with no white splodges.



(and you have BROWN and WHITE/BROWN) as a spare pair if needed at a future date.


That’s it for me explaining on LJU style masters, if going from an LJU master to a custom NTE5,

The Blue wire on pin2 goes to the B connector on the back of the NTE5

And the White/Blue wire on pin5 goes to the A connector on the back of the NTE5.


Now if you have a BTNTE5 or a custom installed NTE5 (see above) then you are all sorted and ready to start the rewiring of your user wiring. If no NTE5 is installed, the next section explains all about installing an NTE5, and the user-wiring. If wiring from an LJU type Master Socket, then that is covered later on.


The face-plate on the NTE5 connects user side wiring to the Master socket by the dummy plug, this goes into the test socket (this is the socket used to test if your user-side wiring is at fault). Before you begin you may want to get the “line stats” from your modem/router, so you can do a before and after. The choice is yours.


However if your line-stats taken from your extensions/face plate, are the same as in the test socket, then no improvement will be found when rewiring to cat5e/6.

The following assumes your master socket is an NTE5 type if it’s the LJU style and you do not wish to install a custom NTE5 then just follow what is said, and mainly look the how to wire extensions (below) because the LJU style extensions are the same as the LJU style master, apart from the extensions do not have the master components fitted.


The NTE5…


I am first going to show you how to wire up your custom NTE5,

Note: I must point out again, read this entire guide before doing anything!

If you have a BTNTE5, then all you will be doing is inserting user-side wiring to the front plate so browse down (or just read on if you are interested).

The information shown here must not be used in violation of RULE-2!


Below shows a picture of the rear of the whole NTE5 unit.

First loosen the A/B screw in plates by unscrewing them slightly.


Below shows my simulated A/B wires, Orange being the B wire and the White being the A wire (its Orange/White because I am using an orange pair from some Cat6 cable)

However your simulated A/B wires should be the Blue/White blue pair coming from your BT LJU style master socket.



Strip around 10mm of sheath from the wire to show the core, (this is the only time you will need to strip any sheath from the main core wire.)


Here shows the wires solid core with some sheath removed.



Next thread your cable under the screw in plates, like below.



Now I do this section so that more cable is making a contact, and a BT engineer has corrected me (see how to do it the BT way in the next few steps). But bend the core of the cable around something small, (like the higher metal part of your screw driver.) see below for the results.


Next gently pull the wires back so the two “hooks” you just made are around the screws,



Once ensuring that no wire with sheath is under the plate, and ensuring that as little cable is untwisted as possible. Screw the plates down tight.



(A small wire-tie can be placed around here. Securing the wires)


A “BT bod” is trained to strip back and then 'fold' back the exposed wire this then just goes under and through one side of the NTE screw in plate, not 'hooked' round as I showed.


The picture below shows the exposed core of the wire more clearly.



If doing it the BT way, follow as said above, or just do the “hooked” method as above, or place the core of the wire under the plate of the NTE screw.



And your done, the A/B cable will go away outside/or to your BT master socket, and yes! As you can see, this is a BT NTE5 I am working on, so thanks to the BT engineer again for supplying me with that for the purpose of helping you all with xDSL J

Now onto the main part, wiring the NTE5 face plate with Category5e/6 twisted pair solid core cable, an how many pages in are we before I got here!?!



Below shows a standard face-plate, yours could be different as it could have six terminals or it could be an ADSL-filter plate.



Remove some outer sheath from your cable (see extension section as I show how in more detail) (so yes READ all of these sections). Around two inch’s should be enough.


Now place the pairs along side of the little holder if there is one and secure them with a wire tie, but take note, not to pull it really tight just yet, and it will need rotating or the faceplate will not fit into the socket. Lay the green and brown pair, around the top of socket out of the way like shown. (If your face-plate is different it is up to you what you do with them), I am keeping them there so you have a spare pair at least, if something goes wrong in the future.



Trim the Green and Brown pair down, but not too short as that they can never be used.



Choose your cutter, you can be using disposable cheap IDC terminators or the actual tool, the choice is yours. I will be using the correct tool as it has little cutters, (see extension section as I demonstrate its use in more detail) (so yes READ all of these sections)


Undo the twists in the pairs as much as is necessary, and lay the wires flat across the correct IDC number, Blue over terminal 2, White/Blue over terminal 5.



Next just simply push down with your tool - all the way down.



Continue to do the other wires, if you are not connecting the ring wire (see Phil’s section for reasons for not connecting this, near the end of the guide) then just move it aside.


If connecting the ring wire, then do so.

When done it should look like this…



Note at the bottom, I have pulled the cable tie further around. Look at the picture of the complete NTE5 unit to see why…


See how at the bottom there isn’t very much room…your face-plate would not have been able to plug into the socket as the cable tie end would have blocked it.



Above shows the NTE5 all done. Apart from you should be using white Cat5e/6 cable (looks nicer in the home/office, but it depends how you want it to look) and the A/B wires will be behind the wall in a flush mount or something. Or the drop cable or what ever could come though a surface mount, either way, it doesn’t matter because this guide is showing you how to wire… remember rule 2?


Now onto the extensions, the following socket shown in the pictures is the LJU2/3A socket.

Here is a picture of the LJU2/1A (Master IDC) and LJU2/3A (Secondary IDC)


(The layout of the PCB can change, so your components can be in different places.)


Assuming you have cut your cable to the right length, and everything is good to go, let’s wire them up.

Cut the plug off the other end, (or if you have a huge amount of cable just cut it when it’s the correct length.)


Now thread the cable through the back-plate of the extension, or if it is a flush mount or surface mount… which ever.

Strip around two inch’s of outer sheath to reveal the twisted pairs.

Then untwist the pairs (as shown below)



Choose your weapon… For the extensions I am just going to use the proper tool as it has the little cutters.



Untwist the pairs and lay the correct colour over the correct IDC number (see the list above) you could also wire-tie your cat5e at this time (go down a few pictures to see).

Start to push down and the cable will be terminated in the blades.


Keep pushing to close the cutters and they will snip the excess cable off.


Now at this point, you can decide if you wish to leave the ringer off (as you can with the NTE5 face-plate),

I connected the green pair and pin4 for neatness. You can just choose to wire the blue pair in to terminals 2 and 5.

Just tuck it up around the socket like I have done with the brown pair, you can choose not to wire the ring wire to pin3 at the master or at all the extensions.


Personally I would wire it all at the extensions and leave it off at the master if you are one of the people who would like to disconnect the ring wire. This would make it so when you wanted to connect the ring wire, you just have to connect it at the master and then you’re done, rather than open all of the extensions to reinsert.

If you are just going to wire all of the contacts then it should now look like below.


Next is to secure the cable to the front of the socket, this can be done first or last or whenever… just make sure its done so yanking on the cable wont cause all of your wires to rip out of the IDC’s.


Pull it tight (but not so it crushes the Cat5e/6). Then just cut the excess tie off.


Next screw the face plate back onto the back plate/wall mount/which ever (I am showing how to rewire), so if you are installing extensions, you should have the basic DIY skills needed to screw the thing to the wall ;-)

Now here is a late addition to the guide, I got hold of an old LJ2/1A (LJU style master socket) Thanks BT!


Below shows my simulated AB wires again, Orange being the B wire and the White being the A wire (its Orange/White because I am using an orange pair from some Cat6 cable)


Here shows the master socket with no extension wiring, the AB cable should go off into the wall or off somewhere… Again the AB cable at this point COULD be blue and blue/white as sometimes BT installs the AB cable to a junction box then uses normal phone cable to the master box. (It could be any colour…!)



Anyway installing your cable to extensions or the custom NTE5 is easy! Just tuck the spare brown pair out of the way again. You can also leave the ring wire off terminal 3 if you wish.



After this the user wiring could go off to the custom NTE5 or to your extensions.


What’s all this about the ring wire removal then?


Many users on ADSL-Guide have found disconnecting the ring-wire from terminal 3 has improved line stats, sometimes in huge amounts. A forum member sent me this information. (I deleted your email, so email me and I will add your name to the Bibliography)

Many years ago the UK telephone system adopted a different policy to that in the rest of the world. Here in the UK a choice was made to move a ring component, which enables the telephone to ring, out of the telephone and into the master socket.

The main reason for this, involved ‘pulse-dialling’, which has now been replaced by ‘tone-dialling. It was a good idea at the time because it made it possible to stop the ‘tinkling’ that occurred on other extensions when a phone was dialling.

However, there was a downside: To get the ring signal into the telephone we now have to run a third wire from the socket to the phone. Also, since we only need one ring capacitor on our line, and it is located at the 'master' socket, we have to take three wires to all our extensions, rather than the two wires which come to the house.

On most modern wiring you will find the original phone signal connected on the 'blue-white' pair of wires (Terminals 2 and 5) and the extra 'ring' signal connected on an orange wire (Terminal 3), though these colour codes are not always followed.

Now, since ADSL filters only filter the main telephone pair, they must re-generate the ring signal themselves. All of this is of only passing interest but it does mean that you only need to feed an ADSL filter with two wires. The ring signal for the third terminal on the attached phone is generated internally. Since most telephone extension wiring consists of two pairs, you may find this information particularly useful if you need to use a particular run of pre-installed cable for both a filtered and unfiltered signal (However Cat5e/Cat6 has that extra pair remember?). It is up to you if you wish to remove the ring wire, and the reasons for doing so are listed later on in a section that Phil, better known as Yarwell from ADSL-guide as written.


If the incoming ADSL signal is weak, or mixing with a lot of interference, it is possible that the layout of the extension wiring within your premises can degrade the signal even further.

If you suspect that this maybe a problem, then you will need to do all you can to optimise the layout of your wiring.

The basic principle is to ensure that there is only one path for the ADSL signal - from your master socket to your modem. If it is running off an extension then there should be no blind alleys caused by t-junctions or branches on the way. All of these blind alleys should be closed off with a filter so that the ADSL signal cannot pass down them.


See Yarwell’s picture he created of his star/spur wiring system.



The best solution is to put your modem next to the master socket using an ADSL face-plate. (NTE5 required). This places the filter as close as possible to the incoming ADSL signal and provides hard-wired, filtered connections at the rear for all the other telephone extension in your house.

The only place the ADSL signal is available is at the front of the faceplate. Unless you make dedicated ADSL extensions, or by using ADSL-Nations faceplate, allow for ADSL and VOICE to the extensions.

Hopefully however no matter how your wiring is laid out, the Cat5e/6 should hopefully have reduced interference with the ADSL signal.


Next we go onto the reason for removing the ring wire.


This section is all of Yarwells work, so thank him for the excellent explanations.


Most broadband in the UK is ADSL supplied over phone lines. This involves a cunning plan to send frequencies of 100 kHz up to 1 MHz (AM through Short Wave radio) along the line superimposed on the low frequency voice signal. This allows speeds of several MBits/s to be transmitted over twisted pair copper cables only ever intended for analogue voice, quite neat really.

Nowadays ADSL is supplied "wires only" i.e. BT put the signal on the line and the user gets to make it work. When the twisted pair phone wire arrives in the user's house it is converted by a "master socket" to a 3-wire system where the 3rd wire provides a ring circuit, originally designed to power clunky bells in old steam phone’s J, see the explanation at http://www.wppltd.demon.co.uk/WPP/Wiring/UK_telephone/uk_telephone.html.

This 3rd wire is a "bit of an issue" as it makes the nicely symmetrical balanced twisted pair into the equivalent of a 3-legged ballerina.

In my case, the ring wire runs around my house as part of the feed to at least 6 extension phone points, in doing so it acts as a nice big aerial (antenna) to collect any radio transmissions and random electrical noise that may be passing through. It then feeds this mush back into one side of the twisted pair through the capacitor that is there to provide the ring signal and consequently degrades the ADSL signal.

This "degradation" appears as a reduction in the signal to noise ratio (SNR), and as CRC errors counted up by the modem and in some cases cause disconnections, or prevents the end user getting the speed their line should be capable of. As we move to faster speeds and to "rate adaptive” services where the ADSL goes as fast as the line allows it, the dear old ring wire will slow down our connections.

So, what to do with the 3rd wire? The Rolls Royce solution comes in the form of an ADSL filtered faceplate (photo below)


This fits onto modern BT NTE5 master line-boxes and provides ADSL and voice on separate sockets with filtered extension wiring connectors at the back. This keeps mush from the extension wiring, including the ring wire, out of the ADSL signal. It also avoids the need to use micro-filters on each telephone appliance (depending on how wired up with certain face-plates), which is A Good Thing™. Also available from ADSLnation.com

However, many of us don't have a nice NTE5 terminating our incoming phone line.

My phone line comes into a junction box in the roof-space from which the wires run in a "star" or spur configuration, the "master" socket is on one leg of the spur system and is identified by having a ring capacitor and a surge arrestor fitted.


As I have no NTE5 I can't use a filtered faceplate without a re-wire, so a bit of innovation is called for.

The photo on the right shows the back of my master socket with the ring wire disconnected from terminal 3, the other half of the orange/white pair is also disconnected from terminal 4. A higher resolution photo is at the bottom of this article.

By disconnecting the ring wire from the master we remove the 3rd leg and restore the balance / symmetry to the line.

Well, so much for the theory, what difference does disconnecting the ring wire actually make? The stats from my router below show the results;

Before, with ring wire (1 hour stats)

LocalSNRMargin = 20.5 dB
LocalLineAttn = 32.5 dB
RemoteLineAttn = 23.5 dB
RemoteSNRMargin = 25 dB
LocalFastChannelCRC = 22
LocalFastChannelHEC = 6

After, ring wire disconnected (20 hours)

LocalSNRMargin = 32.0 dB
LocalLineAttn = 32.5 dB
RemoteLineAttn = 23.5 dB
RemoteSNRMargin = 29 dB
LocalFastChannelCRC = 2
LocalFastChannelHEC = 0

So we see an increase in local SNR margin of 11.5 dB, meaning the router sees 11.5 dB more of the useable signal from the exchange after subtracting the noise. Going the other way the exchange gets to see 4 dB more of useable signal from the router. These figures after rebooting the router so it could adapt to the new line conditions.

20 hours after disconnecting the error counter hadn't shifted from its initial value of 2 errors, compared to 28 CRC & HEC errors in just one hour with it connected. Result!!!

The phones still ring because they are using micro-filters and each of these has its own ring capacitor on the phone outlet side of the filter. If you disconnect the ring wire it would be prudent to re-connect it if you move out of the property, so the next occupier's phones work as expected.


After the success with taking the ring wire off and improving the SNR I was blessed with a free speed upgrade to 2M by my ISP Demon which was facilitated by ADSL-guide getting my entry changed in BT's line prequalification number checker.

This speed upgrade took the downstream SNR margin down to 25 dB, still healthy but I was pleased I did the ring wire thing to improve it. Last night I hooked the ring wire up again and the ADSL modem lost sync, it re-trained to an SNR of 12 dB and ran OK but clocked up errors. The reason I put it back on was to look at the frequency effects of the interference, using a Sagem F@st 800 modem's diagnostic mode.

The first plot is with the ring wire disconnected, showing a wide range of useable frequencies.

The second plot shows the effect of reconnecting the ring wire - it loses virtually everything above frequency band 140 with a consequent loss of ADSL data carrying capacity. The lower frequencies are a lot more ragged too. It would still operate at 2Mbits/s but was clearly less capable than before.

With the higher frequencies rendered unusable by the ring wire interference, the modem is forced to cram more data into the lower frequency bands. This in turn makes it more sensitive to interference as a higher SNR is required in order to use more bits per channel.

So at least we can see why the ring wire impacts the SNR, it is adding interference in the 600 kHz - 1 MHz range. This is AM and short wave radio territory, so perhaps this should not be a surprise - for all I know the ring wire may be a nice wideband AM radio antenna, built into my house :-)

For my final experiment I hooked up a filtered socket from ADSL Nation in place of the master. This provides a filtered and unfiltered socket on the front, and an IDC terminal block for filtered extensions on the back. So I used it to provide me with a filtered ring wire that could supply ringing voltage to all the extensions without compromising the ADSL. This works well and maintained the 25 dB SNR and over 10 hours my router only clocked 3 CRC errors.

LocalSNRMargin = 25.0 dB
LocalLineAttn = 32.5 dB
LocalTxPower = 10.5 dB
LocalFastChannelRxRate = 2272000
LocalFastChannelTxRate = 288000
LocalFastChannelFEC = 0
LocalFastChannelCRC = 3
LocalFastChannelHEC = 0
RemoteLineAttn = 22.0 dB
RemoteSNRMargin = 29 dB

The only point in doing the filtered ring wire bit, as opposed to simply disconnecting the ring wire, is to leave the extension wiring fully functional, such that if you aren't using ADSL any more or leave the property the phone sockets will behave as expected. One wonders if at some point BT will abandon the ring (3rd) wire, it may have made sense 20 years ago for electromechanical bells but it’s a real nuisance with ADSL broadband.

The images below show the "before" bin plot with the original ringwire connected, the filtered ringwire connection and the "after" bin plot using the filtered ringwire.





Finally, just a reminder that the above refers to star or spur wired systems where an NTE5 master socket can't be fitted. The NTE5 filtered faceplate is the preferred solution where it can be used, it incorporates filtered extension wiring and, if needed, an unfiltered extension connection for a modem/router distant from the NTE5 linebox / master socket.

Having said that, one ADSLguide user has reported improved SNR through removing the ring wire from his filtered faceplate - so if you are trying to squeeze the last few kbits/s of speed or are trying to make a dead or unreliable line work it may be worth a try.


Here are results from rewiring to Cat5e/Cat6 cable, users removing the ring-wire, and users fitting filtered face plates,


Take this as a rough guide of what you could expect to see, the following could have had damaged internal wiring, device’s that produce a lot of different interference near the line, badly terminated wires, also the amount of cable they have will affect it differently, so comparing the differences is hard to see.


These are all from different premises.


From rewiring to cat5e,


“Downstream SNR increased to 12.5 from 8 and the attenuation reduced from 52 to 48”

“Downstream SNR increased to 28 from 21 and the attenuation reduced from 43 to 42”

“Downstream SNR increased to 32 from 29.5 and the attenuation reduced from 24 to 15.5”

“Downstream SNR increased to 30.5 from 26 and the attenuation reduced from 23.5 to 23”


From removing the ring-wire on AFAIK, normal cable,


“Downstream SNR increased from 30.0 to 33.0 and attenuation reduced from 20.5 to 19.5”

“Downstream SNR increased to 19-20 from 9.5”

I improved my rate adaptive connection from 5.6 MB to 5.9 by removing the orange wires from terminals 3 and 4”


A final note; “after disconnecting the ring wire at the master my SNR increased by 8db, I have two extension socket’s; I found that disconnecting the ring wire in these gave me another 2db increase.”


From fitting an NTE ADSL face-plate,


“Just stuck an XTE-2005 on my socket,


SNR 3 (ranging from 0 db to no higher than 16) ATT 48 db
SNR 27 (now down to 24, so far hasn’t gone lower) ATT 46 db”

Downstream SNR increased to 23 from 7 and the attenuation increased by 3





Please send in your results to be added to this section.




Installation and Connection to Direct Telephone Lines

It’s important to follow good wiring practices on fitting equipment to your telephone line to ensure that your extension socket and cabling will not endanger the public telephone networks, as well as giving you trouble-free service of course.

Each telephone exchange line coming into your home or office should be terminated by means of an LJU style “master socket” or an NTE5 “master socket” (identifiable by its removable lower front panel, just read all of the guide).


Extension sockets must always be placed at least 50mm (2 inches) from mains electrical outlets and must not share wall fixings or back boxes with electrical outlets.

Take care in bending telephone cables that kinking or other damage is avoided.


Installing the cable

Do not wire the new cabling into the BT master socket until cable installation work is completed.

There must not be more than 50m (164 feet) of cabling between your master socket and the last extension socket on your circuit. The cabling must at all points be kept at least 75mm (3 inches) from mains electrical cabling and long runs parallel to mains cabling should be avoided. If you’re cabling needs to cross an existing mains cable, the crossing should be made at right angles wherever possible.

Where cabling passes through a ceiling or floor void it must be fixed wherever necessary to ensure separation from mains electrical cabling.

All bends in the cable should be no sharper than25mm (1 inch) radius. On no account should staples be used to fix the cat5e/6 cable; only use suitable cable cleats 5mm size (depends on type of cable you are using)



Avoid kinking or crushing the cable. The UTP (Un-shielded twisted pair) cabling and telephone extension socket are not designed for use outdoors or undue damp or condensation. Installation should be avoided near to sinks, wash basins, showers, baths, cookers, damp walls, window sills and newly plastered walls.

Extension sockets should always be mounted vertically and never horizontally on window sills. Extension sockets should not be mounted on skirting boards.

Care should be taken to avoid damp conditions, so installation in bathrooms and toilets, kitchens and swimming pool areas or similar is not recommended.

Suggested method of installation

Lay the start of the cable at the master socket into which it is eventually intended to be installed.


Uncoil the cable along the path where you’ll be securing it, until the position where the extension socket is reached. Ensure that the installation guidelines for cabling are complied with and that there’s sufficient slack in the cable to enable the wires to be easily inserted into the terminals.

Remove cable entry cut-outs in the extension socket back box if and as required, and mount the back box to the wall in the required position using an appropriate method for the relevant type of wall surface/material.

Cut the cable to the required length, ensuring that there is sufficient cable to pass through the cable entry cut-out in the socket back box leaving sufficient length work freely with the wiring and to enable the cable to be connected to the IDC/Screw type terminal connector’s on the socket front panel.

Pass the cable end through the appropriate hole in the socket back box and strip back the outer sheath by approx 50mm (2 inches). Push the wires into the terminal connectors using the correct tool, ensuring that the wiring connections are made. Then use a wire-tie to ensure the cable is secure.

Attach the socket front panel to its back box, ensuring that there are no trapped wires, using the two screws.

Once the extension socket has been installed, the cable may be inserted into the master socket front-plate. Your extension socket is now ready for use.


Test the circuit’s operation at this stage before securing the cable with all of the cleats.


Finally secure the cable to the wall using appropriate cable cleats, in the case of UTP solid core category 5e cable, 5mm cleats such as sold by Clarity or B&Q, or from most hardware stores. Cleats should not be hammered in really tight, and ideally should be placed at UNEVEN intervals.


IMPORTANT: You must NOT use cable staples to secure this kind of cable as you’ll almost certainly pinch and damage it!


However you could find it easier to lay the cable at the start (near the master socket) and leave an extra 15cm cable (to be cut down when wiring begins), then secure the cable in places until the extension socket is reached. Then start wiring, and test, then secure the rest of the cable nice and neatly.




PSTN master socket contains

  • 1.8uF ring capacitor
  • 470KOhm resistor
  • 26A surge arrestor.


IDC terminals should have no more than 2 wires in each.

M= Master, E= Extension.


So M---E---E---E


As you see… the master will have one wire in each of its IDC’s the first extension will have two, the second will have 2 and the third will have one (until you add a fourth)




  • ADSLguide.org.uk – Your guide to broadband internet.
  • ADSLNation.co.uk – The place to get the XTE2005 ADSL faceplate and XF-1e Micro-filters. It’s all top notch stuff.
  • B&Q – good place to get DIY stuff.
  • Clarity.it – has lots of guides and information, pictures, and it’s a good place to buy custom NTE5 units, plain white solid core cat5e cable, BT ADSL-faceplates and tools.
  • Ebay.co.uk – Good place to buy anything really…
  • Ebuyer.co.uk – Good place to buy Cat5e/Cat6 cable.
  • Google.co.uk – used to search for a lot of stuff including images.
  • TelephonesUK.co.uk – Table on socket sizes, and information about LJU’s.
  • Wikipedia.org – used to find information about the different category’s of cable
  • Yarwell – for the information on why removing the ring wire helps so much.


Oh and myself, a lot of the images and text were provided by myself.


I hope this guide helps you all.