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Your guide to master sockets

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Your master socket is a white plastic box built into your wall, usually in your hallway or near your front door. It’s bigger than a normal phone socket because it’s the point where the external phone line comes into your home.

It's best to connect your router to your master socket. You can also use your master socket to troubleshoot problems with your internet, particularly if it has a test socket inside. 

Not all houses have one, but if yours does, it'll look like one of the below:


Non NTE master socket


NET 5 master socket


NTE 5C master socket


FTTC master socket


NTE 2000 master socket

NTE 2000

NTE 5C MK 4 master socket



Openreach can replace or relocate your master socket and phone line for a fee. If you need a new master socket or you want to move or replace your existing one, please contact us to arrange an engineer visit.

There are two types of master socket. The way you connect your phone and broadband depends on which one you have.


Standard master socket

Standard master sockets have one port on the front, which means you need a microfilter to connect your phone or router. You'll also need to use microfilters in every other socket you're using in your home. 



Pre-filtered master socket

Pre-filtered master sockets have two ports on the front, which means your line is already split between your phone and broadband connection. You can plug your phone and router straight into a pre-filtered master socket without using any microfilters. 


Connecting to your test socket

Your test socket is inside your master socket. It lets you bypass the internal wiring in your house and connect directly to the phone line outside, making it the ideal place to test your internal wiring for faults.

  • Master sockets that have two ports or one port with a horizontal line across the front contain a test socket.
  • Master sockets that have one port without a horizontal line don't have a test socket. If this sounds like yours, please don't try to unscrew the faceplate.
test socket yn-01.png


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

  1. Carefully unscrew the faceplate on your master socket with a screwdriver. If your master socket doesn't have screws, squeeze the sides of the faceplate to detach it
  2. Now gently pull the faceplate towards you
  3. With the faceplate removed, you'll see the test socket inside. It looks similar to the phone port on the front of your master socket but without the sliding cover
  4. If you're testing your router, plug a microfilter into the test socket
  5. Then plug your router's grey broadband cable into the microfilter's ADSL/DSL port

If your connection improves whilst you're connected to the test socket, then the problem is probably in your home. However, if the problem continues, then there's likely a fault in your local area.


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