Digital conference bridge

US3937898A · kind A · utility

Assignee

• International Telephone and Telegraph Corporation · US

Inventors

• Anthony Frank Presto · Nutley, US
• James Dunn · San Diego, US
• Thomas Chen · Tustin, US

Key dates

• Filing date: Jul 18, 1974
• Grant date: Feb 10, 1976
• Expiry date: Jul 18, 1994

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04M3/569
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

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.