Testing your BT TwinTalks at your BT master socket
Make sure you have unplugged all of your other phones, faxes, PCs, answer machines and Sky Digiboxes and all your other TwinTalks and anything plugged in to your extension phone sockets. Plug one of your BT TwinTalks into your master socket and plug a phone into it. Make sure the switch is set towards the TwinTalk phone socket. Call your existing phone number.