Usually, multiple cables are laid in a cable route. After the exact position of the fault is found and uncovered, the defective cable must be identified reliably. Cable identification is used to identify single and multi-core cables in a cable loom. The engineer is provided with precise information as to which cable needs to be tested and, where necessary, cut.
These units operate by method of a transmitter and a receiver, so the operator connects the tester to the cable under test and sends a signal down the cable and then looks to receive the signal further down the line on the cable with the receiver.