Bell Telephone Laboratories

At&t Information Systems Inc.

Clair A Buzzard

Robert Michael Zachok

Leslie A Baxter

Paul R Berkowitz

Frank William Lescinsky

Kent Vincent Mina

Heinz Kahlbrock

Gary J Burns

Richard Cyril Gifford

Henry C Bauer

Robert F Ricca

Travis H Gordon

There is disclosed a multifrequency tone distribution arrangement for a communication system having a common time division multiplexed bus in which digital samples of tone frequencies are supplied from a central signal generating circuit to system port circuits via selected time slots. Each port circuit automatically accepts selected signals from the common bus for conferencing to produce multifrequency digit tones and service tones.

Multifrequency tone distribution using a conferencing arrangement

In time division communication systems one conference technique is to have a processor combine those samples going to a particular station forming a conference having as many subcombinations as there are stations. This approach, while allowing individual station gain adjustment, suffers from its dependence upon a large number of logic operations for a given conference. A modification of this technique is disclosed which uses a distributed structure such that the individual station ports, under local memory and processor control, operate to combine selected time slot samples into a conference sum unique to the station. In this manner gain values may be assigned on an individual listener station basis while the logic processing for the conference is performed in parallel by the ports involved in the conference.

Distributed digital conferencing system

A central controller (104) for a multipoint polling system arranged to collect inquiry messages from data terminals (102a-n, 103a-n) for processing by a data base (101) and for distributing response messages to the terminals, the several terminals using different communication protocols. The controller includes a RAM memory (203) which stores a list of items, each item identifying a terminal and the type of protocol used thereby, a ROM memory (202) which stores an instruction set for each protocol type and a microprocessor (201) which sequentially accesses each item on the list to poll the associated terminal and accesses the instruction set identified in the item to control sending and receiving equipment to query and intercommunicate with the selected terminal in accordance with the accessed instructions.

Collection of messages from data terminals using different protocols and

A memory array, having a plurality of intersecting rows and columns, stores digitized speech. Each row and column intersection consists of a binary storage cell for storing one bit of digitized speech. Incoming digitized speech is loaded into columns of the memory array in a plurality of repetitive loading sequences, each loading sequence including: reading out the bits stored in successive rows of binary storage cells, replacing in each successive row of bits, a predetermined one of the bits in the read out row with a successive one of the bits of the digitized speech and writing each read out row of bits including the replaced bit back into the row. Multibit binary grunts (digitized speech segments) stored in the array are read out therefrom by applying the bits of the grunts to time slots in frames on a time-division highway, each frame being of n bits duration and including one bit from each of n grunts stored in the array. A selected grunt is extracted from the highway by commencing a count of the bits on the highway with a first bit of the selected grunt and by extracting the first bit and every n.sup.th bit thereafter. Memory malfunction is indicated when the number of rows in the array containing parity errors exceeds a predetermined threshold number.

Data access circuit for a memory array

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Lincroft, NJ, United States of America

Clair A Buzzard