TELEPHONE CONTROL CRITERIA IMPLEMENTING A DISABLED LINE CONTROL CRITERIA

摘要

Interference insensitive line supervision circuit for subscriber's line having a given working range for the line potentials. A call can be simulated by the occurrence of overvoltages. Means are applied which supervise the occurrence of overvoltages. In the case of overvoltages these means produce control signals which result in that the state of a line state store cannot be affected by the line supervision circuit.