APPARATUS FOR PROVIDING A GROUND REFERENCE FOR TELEPHONE CUSTOMER SPECIAL CIRCUITS POWERED FROM A FLOATING BATTERY FEED

摘要

when using a battery feed circuit for floating telephone lines, it is desirable to provide a circuit to prevent the corrosion of polarization voltage on conductors leading edge and neck to become positive. this can be done by using a protection circuit (300) that absorbs a quantity of advanced dynamic driver.a circuit including such a line polarization, however, is incompatible with special lines such as pbx (private power lines connected to the public network), which is dependent on a high conductor grounded during a conversation.according to the present invention, a constant current circuit is brought down to the reference driver (400) of these lines. only when there is a transition from a current loop.the intensity of the current supplied is such that the protection circuit (300) is sufficiently close to the potential driver of high land to allow the proper operation of the circuitry connected to the lines.