Telephone Line Help Page

Useful telephone Information

Test your phone in the master socket before contacting your service provider!

Until recently British Telecom were responsible for providing and maintaining your phone line. However OFTEL have now allowed other companies to provide telephone services and therefore BT do not directly maintain any phone lines or equipment, even if you pay your bill to BT. This job is now the responsibility of Openreach. Openreach are the only company that can maintain your phone line up to the demarcation point in your premises.

What is a demarcation point? Normally it is a NTE5 or master socket like the one pictured below, however it could be any number of other connection points depending on how your phones have been wired in the past.


nte5 ……….

The NTE5 Master socket was introduced in 1986 to permit DIY extension wiring. Most lines now have an NTE5 installed and this is the point that your service provider will guarantee the phone service to. Any wiring past this point is your responsibility to maintain. If you have a fault on your wiring it is a good idea to test the line at the internal NTE, by removing the face plate and plugging in a phone to the internal socket. If the fault still exists at this point then contact your service provider to report the fault.

You are allowed to install extension wiring so long as the connection to the master socket is via the special terminals provided on the lower section. When the front screws are removed from the NTE5 the complete lower portion of the socket can be taken off. On the back of this lower section are the terminals for extension wiring. The lower section is connected to the back of the box using a plug built-in to the panel. The built-in plug is a standard BT plug and the socket in the box is a standard BT style socket. This arrangement means that all the internal wiring can be easily disconnected for fault finding. The socket in the back of the box can then be used to test if the line is working. When calling your service provider to report a fault they will often advise that you remove this lower section and connect a phone to test the line before sending an engineer. If you are unsure about completing this the we can send an engineer out to complete this test for you and diagnose any faults that exist. Our call out charges are a lot less than your service providers!

External NTE

The demarcation point may now be outside of your property. Openreach are now rolling out the external NTE, like the one pictured below. They will maintain the phone line up to this point, all of the wiring feeding from this unit into the property will be the owners responsibility. If you are buying a new home with one of these external NTE’s then you may need wiring run from this into any sockets the builder may provide.

Types of cable

There are considerable differences in the types of cable used for wiring telephone extensions. Many low cost extension kits from DIY shops and electrical retailers use low cost, low quality general purpose signal wire which has aluminium or braided wires. This type of cable is used mainly for alarm installation and is not recommended for extensions that will be used on an ADSL enabled line. The reason being that the typical low cost cable is straight the cable that has no protection from interference. There are a great deal of possible sources of interference in the home or office so it is far better to use cable that has some way of reducing interference. All the cable used by our engineers is CW1308 standard, 0.5mm copper conductors. This means it is exactly the same quality of cable used by Openreach engineers, and is designed specifically for telecom lines.

Useful Contact Numbers

BT Faults 151 or 0800 800 151
Virgin Media 151 or 0845 454 1111
Talk Talk 0870 087 8777
First Telecom 0845 215 1640
Kingston Communications 0800 915 5112
Post Office 0845 600 3210
Sky Talk 08442 410564