POWER LINE COMMUNICATION SYSTEM

摘要

This invention relates to a power line communication (PLC) system (8) wherein the power supply line supplies power and also acts as a communications supply line. A receiver (30) is able to detect small changes in the modulated transmitted information and thereby shut down the circuit. The invention is particularly suitable for use where the IEL is remote from the power supply such as, for example, in down hole oil production situations where very long power cables are used.