extend the circuit just like you were running a data cable. it will extend all 8 wires in a straight through configuration. Furbal is sort of right but a 56k line is an RJ48. RJ stands for registered jack which is defined by the circuit it is connected to. Everyone uses RJ45 to define an 8 conductor jack or plug but that is actually an improper use. and yes, a 56K uses 1,2 and 7,8 or blue orange and brown slate/white