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BT telephone wiring, colour codes, common faults & cable quality
April 28th, 2016 11:54 am

In this post we cover some common BT wiring faults/mistakes, colour code schemes & why cable quality with broadband is VERY important! We also explain the bell wire & why you really want to have the latest NTE5 and most probably a SSFP too (what on earth is an SSFP you ask?! Well read on to find out!!......

Some common faults

Phone ringing continuously
Terminals 2 and 5 swapped between sockets (2 at one socket connected to 5 on another and vice versa)
No ringing
Terminal 3 disconnected

Ringing but no speech (or very poor speech) and can't dial out.
Wire between terminals 2 or 5  broken.

Very poor speech quality, possibly poor bell
Terminal 3 and 2 or 3 and 5 transposed

Colour Codes

BT Openreach are using new cables with new colour codes. The old wiring scheme was as follows :-

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
Connector 3 - Brown
Connector 5 - Orange

The ring wire or bell wire

You have most probably heard of the "ring wire" or "bell wire" & why it is bad news for ADSL & vDSL broadband. Removing the bell wire (pin 3 on the IDC block of the MASTER socket, eg, NTE5) can certainly improve ADSL/vDSL performance if you have internal extension wiring (if you don't have any extension wiring then you shouldn't have a bell wire!). However removing the bell wire is against the BT wiring specification. So what can you do? Well, the good news is BT along with their suppliers cured this problem with the addition of a bell wire filter (or inductor to use the correct term) which is fitted to the latest BT NTE5A socket (which we sell!). In short the addition of a 22mH choke on the circuit effectivily removes the bell wire from the equation while leaving it in place to do what it is there to do!!

So w...