Guide to phone sockets

Your master socket is the point at which your telephone line enters your property. It's where to connect your wireless router in order to get the best performance and fastest broadband speeds. Your master phone socket can usually be found in your hallway or near your front door and will be bigger than any other socket in your house.

Single / standard socket

If your master socket has one socket (like the ones pictured below) then you’ll need to use a micro-filter for every other phone socket with phone or broadband equipment plugged in. This includes your wireless router, phones, answer machines, TV boxes, alarm systems and anything else that uses a connection. These filter your phone line and let your broadband and phone work together at the same time. You receive a micro-filter with your wireless router when you join. If you need others, they are available from most electronic retailers.

Double / pre-filtered socket

If your master phone socket has 2 ports this means it’s a pre-filtered master socket, so your line is already split between your phone and broadband connections. You can just plug your phone and wireless router straight into these sockets without using any micro-filters.

What's a test socket and a faceplate?

If you're having problems with your broadband speeds, our Technical Support team may ask you to try the connection in the test socket to rule out any issues with the internal wiring in your home. Master sockets that have two ports or one port with a horizontal line across the front contain a test socket.

NOTE: Please skip this step and do not unscrew the faceplate if there is no horizontal line dividing the front plastic cover.

Here’s how to connect your router to your test socket:

  • Unplug all telephones, PCs, routers, extension leads and adaptors, and double adaptors from all your telephone sockets. If you have broadband, don't forget to unplug all micro-filters and your router from the telephone sockets as well
  • Carefully unscrew the master socket faceplate with a screwdriver. If it doesn't have screws, squeeze the sides of the faceplate to detach it. The front plastic cover may not remove completely so should not be pulled away with excessive force
  • With the faceplate removed, the master test socket should now be visible on the right-hand side of the socket
  • Plug one of your micro-filters into this test socket
  • Plug your wireless router's grey broadband cable into the micro-filter port labelled ADSL
  • Now run a speed test and note down the results you get


If you are now receiving higher broadband speeds in the test socket, it’s likely that your internal home wiring is the source of the problem and in turn is causing your speed to be reduced. You may need to consider getting an expert or electrician in to repair or reinstall the faulty wiring. Slower or similar speeds indicate a fault with the phone wiring outside your home or the network.

Existing customers

Broadband and HomePhone Support

8am to 8pm, Monday to Saturday

9am to 6pm, Sunday

0345 600 3210

0345 600 3210