Short-circuit detection circuitry for telephone subscriber line

摘要

The short-circuit detector (KE) is coupled to a common circuit node (PK) which is connected to at least one of the line wires via a blocking diode (D1). The short circuit detector responds to the voltage dropping below a given value in response to a short-circuit, and controls a voltage regulator (SR) for rapid reduction or disconnection of the supply voltage provided via the subscriber line.Pref., the short-circuit detector supplies a short-circuit indication to a control unit within the exchange for initiating a line short-circuit protection sequence.