I need to run a telephone line upstairs to the bedroom. The previous cable played up causing the phone to crackle so I removed that and have started to run the new lead up the stairs. Now I bought a cable roll that had a connector that plugged into the existing main plug at the front door. The cable roll looked long enough but of course it is not. Now the other end of the cable is just that, an end with no connector. I need to get some more cable and extend the run through the bedroom door frame and that will have to have a terminal box on it to plug the new phone in. My question is how do I join the two runs together and is there a off the shelf roll with the terminal box on it that I can buy?