I have 2 phones lines (cira 1955)that come in separately on a 3 wire(all black) twisted cable, only using 2 wires, to the interface, and then on to a jack, again using 2 of the 3 wires of the same type of cable, rather than the more common 4 wire cable consisting of red, green, yellow and black. Can this 3 wire cable support 2 lines, using one of the wires as a common for the 2 lines, in order to bring the 2 lines to an existing jack location? Thank You