Abstract: A circuit which performs loop supervision, transmit, receive, and transmit and receive regulation and sidetone balance. A loading circuit shunts excess current from the transmit and receive circuits under short loop conditions. The loading circuit also controls regulation of the transmit and receive circuits. Use of constant current power supplies external to the transmit and receive circuits prevents modulation of the power supplies.

Abstract: An electronic tone ringer for use in telephone substations. This circuit operates in response to conventional ringing signals and generates a single tone alert signal interrupted at a low frequency. The audible tone alert signal is generated by a piezo-ceramic transducer.

Abstract: Monolithic integrated circuit structure incorporating a full wave diode bridge rectifier of four Schottky diodes. A body of silicon includes four zones of N-type material. The first and second N-type zones are separated from each other by encircling and intervening P-type material. A third and fourth N-type zones are contiguous. A Schottky barrier is formed adjacent to the surface of each zone by a layer of a mixed silicide of deposited titanium and tungsten. A first conductive member is connected to the N-type material of the first zone and the silicide layer of the third zone. A second conductive member is connected to the N-type material of the second zone and the silicide layer of the fourth zone. A third conductive member is connected in common to the silicide layers on the first and second zones. A fourth conductive member is connected to the N-type material of the third and fourth zones.