How to Wire a DSL Jack | Techwalla Phone lines consist of four-strand wires, including two transmit and two receive frequencies. Newer installations often use Ethernet cables, which still use the same two frequencies but also have extra wires for forward compatibility. A DSL jack is identical to a phone jack, except that the extra transmit and receive wires are connected. DIY Home Telephone Wiring - Easy Wiring a jack is not difficult and it is totally fine to add a new jack or internet phone jack to your system. You should disconnect the main phone line from the source before continuing wiring a phone jack. The phone line usually comes in by your electrical panel. There will be a small box with a phone line going in and coming out.