How to connect your UK BT telephone

Master and Extension sockets are identical except that the Master socket has additional components:
A gas-discharge voltage-surge suppressor.
A 4k7 resistor to "loop the line".
A 1µ5F capacitor to pass ringing current but not d.c.

Connect incoming line wires to terminals 2 and 5.

BT telephone socket

A common cause of problems is dampness, which causes corrosion of the wall socket connections. You can cure or avoid this by making fresh connections and coating them with silicone grease. Click HERE for info.

Silicone grease

Wire extension socket to master socket.. wiring terminals 2, 3 and 5 together.
2 and 5 should be a twisted pair since these carry the voice. 3 is used to disable ringing when the handset is lifted.

UK Cable colour convention:-

Red/blue/green/white is the standard for British line cords. The colours match up with the fixed wiring and jack terminals as follows:

2 = Red (or Blue with white tracer) <-----
3 = Blue (or Orange with White tracer)
4 = Green (or White with Orange tracer)
5 = White (or White with Blue tracer) <-----

Only 2 and 5 usually need be connected.

More info click

Fit socket so that plug clip fits on the right side. The sliding cover should slide upwards to open.

Plug has a spring clip to keep it in the socket. The clip is designed to break if someone pulls- or trips over- the cable.

A cord with plug can be fitted to the old fashioned "746" telephone as shown in the sketch.

Not approved by British Telecom or other telecommunications companies

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