Carrier Frequency Trunk Cables

A star quad cable is normally used for these cables, which are used in pairs, one for transmission in each direction. These cables, from 0.4 to 0.05 in. (1.0 to 1.27 mm), avoid cross talk between cir­cuits. The frequency of each message is changed to a higher pitch so that up to 60 individual messages can be handled in one pair of wires, all at different carrier frequencies which are filtered out at the receiving end and restored to audio fre­quency.