At&t Bell Laboratories

Charles H Sharpless

William F MacPherson

Bernard T Sander, Jr

Eugene J Theriot

Robert W Van Slooten

Mark M Chodrow

Robert C Hudson

An arrangement comprising a host switching system and a number of remote switching modules which are directly interconnected such that voice and data traffic as well as control information can be conveyed between modules without being routed through the host system network. The arrangement allows the integrated stand-alone operation of the remote switching modules and advantageously reduces traffic through the host system network during normal operation. Each remote switching module selects the channels on the interconnection to the host system which are used for conveying information between the host system and the remote module.

Switching system having remote switching capability

In a stored program controlled electronic telephone switching system transmission links are provided from a host office, provided with a central processor, to one or more remote offices, each provided with a remote processor. Data and control information are continually passed between the host office and each remote office in a digital time-division format. Data integrity is monitored through a cyclic odd and even patterned parity scheme which predetermines the parity of sequential time slots in one direction of transmission and reflects that parity pattern in the return direction of transmission between host office and remote offices. The patterned parity scheme detects hardware faults in the interface for the transmission links between host and remote offices on a continuous basis.

Parity checking arrangement

A floating battery feed circuit comprising a switching-mode, flyback power converter wherein a capacitor connected to a converter transformer winding develops a relatively low voltage used to energize the converter control circuitry. The converter control circuitry prevents the operation of the battery feed circuit unless the voltage developed by the capacitor is above a predetermined magnitude. The power converter advantageously operates in only a constant-power mode regardless of loop impedance.

Growing community of inventors

Wayne, IL, United States of America

Charles H Sharpless