[PDF] Lets go over the basics of telephone wiring. Lets go over the basics of telephone wiring. Once you understand the basics, troubleshooting becomes a breeze. The network interface acts as your main junction box- the place where all telephone cables leading into your house originate. Usually, part of it is off limits to you. one telephone line and one telephone. A single wire entered Fix Your Home: Telephone Junction Box Sep 10, 2011The telephone junction box is the hub where all telephone wires inside your home converge. Its main function is to act as a hub that will distribute telephone power and signals to telephone jacks inside your home.