If you're experiencing an intermittent or slow broadband connection you'll often be asked to see if your connection improves while connected to the 'test socket'. The test socket is simply a phone socket that connects directly to the phone line rather than looping around your home.
How do I access this test socket?
You'll first need to check if your master socket is one with a test socket. You can identify a NTE5 BT socket by the horizontal strip across the middle.
You'll need a screwdriver to undo the two screws so that the lower section can be removed.
Once you have removed the the lower half of the phone socket, you should see another phone socket to the lower right hand corner. This is the test socket. Connect your filter into the test socket.
Once connected you might start to see an improvement on stability and speed in your connection. If you don't see an improvement this could point to an equipment or line issue.