International Telephone and Telegraph Corporation

Anthony Frank Presto

James Grant Dunn

Thomas Chungmin Chen

There is disclosed a digital conference bridge for a delta modulated switching system having information transmitted by delta modulation bits in M channels of a time division multiplex frame, where M is an integer greater than three. N conferees, where N is an integer greater than two but less than M, are interconnected by a time switch to enable a conference to take place among the conferees. N three stage shift registers are provided, one for the delta modulation bits of each of the conferees. N sequence detectors are coupled to an associated one of the shift registers to produce a binary 1 output when bits stored in the shift register are all binary 1 or all binary 0. N counters each have their count increased by the binary 1 output of an associated one of the sequence detectors. A count comparator is coupled in common to all the counters and produces a control signal indicating a new speaker for the counter having the largest count. A selection matrix is coupled to each shift register and responds to the control signal to couple the delta modulation data of the new speaker through a one stage memory to the time switch for distribution to all of the conferees.

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Nutley, NJ, United States of America

Anthony Frank Presto