Plugging your router into your test socket is a good way to find out if there's an issue with your external wiring; however, not all main phone sockets have one: Main phone sockets that have two ports or one port with a horizontal line across the front contain a test socket. Main phone sockets that have one port without a horizontal line don't have a test socket. If this sounds like yours, please skip this step and don't try to unscrew the faceplate. Here’s how to connect your router to your test socket: Carefully unscrew the main phone socket faceplate with a screwdriver. If it doesn't have screws, squeeze the sides of the faceplate to detach it With the faceplate removed, you'll see the test socket inside. It looks similar to the phone port on the front of your main phone socket but without the sliding cover Plug a microfilter into the test socket Plug your router's broadband cable into the microfilter port labelled ADSL Now run a speed test If your speed improves whilst you're connected to your test socket, there could be a fault with your internal wiring. Slower or similar speeds could indicate a fault with the wiring outside of your home.