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NTE5 sockets
January 12th, 2016 4:09 pm     A+ | a-
One of the most popular items we sell is the humble BT NTE5 socket. The first question is usually "Do I have one?!", well, this is what it looks like :-

Openreach NTE5 socket
The easiest way to identify it is by the horizontal split just under half way down. Removal of this lower section reveals the much talked about "test socket".
NTE5 test socket example


In reality all the test socket does is allow you to plug a telephone directly into the incomming line without any extension wiring connected. Why would you (or a BT Openreach engineer cheeky) want to do that you may ask? Well, BT is responsible for any cabling upto the NTE5, any internal extension wiring is not their problem. By removing the lower front half they can easily test their side of the cabling from the exchange and lay blame for any faults on your internal wiring blush

What if I don't have an NTE5 you may ask? Fear not as we have plenty we can sell you yes

https://www.bttorj45.com/telephone-sockets/nte5a-socket-openreach-branded/

We also have a non branded version, made by the exact same company that makes them for BT (for the record a company called Pressac, no they won't deal with you direct!). Because this is not branded it has the added bonus of being slightly cheaper...

https://www.bttorj45.com/telephone-sockets/nte5a-master-socket-unbranded/

Now, the official line here is you are not supposed to fit your own NTE5, oh no! What you are supposed to do is call BT (or your provider) who will get an Openreach "engineer" out to fit one for you, they will also relieve you of about £135 + VAT for this 5 minute job! The reality is we have been selling NTE5's for over a decade, not one person has got into any trouble & providing you follow the simple installation instructions below you really can't go wrong! If you do then hang you head in shame & get someone who can push two little wires into two slots surprise

So, to install, take the line pair and using an IDC tool push these into A & B on the rear of the NTE5 :-

NTE5 A & B Connections
& if you don't have any extensions wired up then that is that! We told you it was easy but you didn't believe us did you?! If you do have the need for extensions then it gets really complex....laugh

Extensions are wired to the lower front half, remember we covered that with the test socket-wake up at the back!! So, to wire an extension you wire to 2, 3 & 5 on the lower front plate as seen here :-

NTE5 extension wiring terminals

The official colour code is as follows (older wiring) :-

Connector 2 - Blue with White Rings
Connector 3 - Orange with White Rings
Connector 5 - White with Blue Rings

This has now changed to :-

Connector 2 - Blue
Conector 3 - Brown
Connector 5 - Orange

The same colours that you fitted to the NTE5 go into the corrosponding connections on the secondary extension socket. Sorry, we lied when we said it was really complex devil

The circled part is what we call a bell wire (or ring wire) filter (its actually an inductor so there!), more on that below cool

So, in main that is what an NTE5 is & what it does. There is some more information that is of interest & we'll cover that now.

The bell wire or ring wire issue....

As mentioned above there is a little device known as a bell wire or ring wire filter. This was added to the NTE5 design in 2008. In short with the advent of ADSL it was discovered that download speeds could be improved by unto 4mb by removing the ring wire (pin 3 on the extension wiring). However a lot of phones still require pin 3 to ring so this was not ideal. The solution was to add a 22mH inductor or choke which effectively isolates the ring wire from the ADSL (& now vDSL, it wasn't invented back then!) signal. The issue is basically electrical noise picked up on the 3rd wire, the line pair (2 & 5 or A & B) cancels noise as that is a characteristic of a twisted pair, the ring wire is not a pair so can pick up noise. To see if your NTE5 has a bell wire look for a small plastic cylinder on the lower front plate as circled above. Now, for some reason, this was added to the plastic before the circuit design was 100% ready so there are faceplates out there that appear to have the part fitted but in fact don't. The only way to be 100% sure is to unclip the two parts & check the actual faceplate for the inductor. Note that all of this only applies if you have extension wiring, if you don't then adding an NTE5 with a bell wire filter will do nothing at all. There is another design change that can improve ADSL & vDSL connections however so read on......

 The 26A surge arrestor issue....

What on earth is a 26A arrestor you maybe thinking!! Well here it is in all its glory....

NTE5 26A surge arrestor

The little black item is what we are discussing here. The large yellow part is a capacitor, this generates the voltage for the phone to ring. The blue item is a resistor & is used for line test purposes. The 26A was removed from the design in 2012, this was done at BT's request, according to them this device affects ADSL slightly (& more so vDSL connections) & hence the decision was made to omit it from the design. Although speed increases are minimal compared to any ring wire issues there is an improvement so this can only be a good thing. Here's the latest PCB revision without it fitted :-

NTE5 26A component removed

Now you may be thinking why do I need an NTE5 and what's the big deal? Well, if you have broadband, & let's face it most people do these days you really should be thinking about installing what is known as an SSFP or Service Specific Face Plate. We'll cover those in our next post.....
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