Ipc Information Systems, Inc.

International Telephone and Telegraph Corporation

International Standard Electric Corporation

John M Cotton

Nicholas Necula

Enrique Abreu

Neil C Olsen

Alex T Wissink

Alan J Lawrence

Gary V Pieper

William A Oswald

Bidyut Parruck

Jeffrey N Denenberg

Maurice J Mascarenhas

Rudy De Bruyn

Fryderyk Tyra

Daniel C Upp

Robert Treiber

John E Cox

Francoise C Van Simaeys

Anna M Leurs

Kenneth F Giesken

Kenneth J Hamer-Hodges

A clocking mechanism with improved fault tolerance for synchronizing a distributed processing system includes a plurality of distributed clock sources. Each clock source may operate as a master clock for synchronizing the operations of the entire system or as a slave to an external clock while remaining available, in a backup capacity, to operate as a master clock in the event of a failure in the previous master clock. A clock selection mechanism is provided in each distributed switch element for selecting the best clock available to each switch element for synchronization. A failure recovery mechanism is provided with fast and automatic recovery in the event of a failure in a master clock. A data extraction mechanism is also provided capable of sampling a bit stream that is not phase-aligned, even in the presence of timing jitter and pulse width distortion, and having provisions for detecting a bit slip.

Distributed clocking system

A channel allocation system for selecting the earliest available switch port and time division multiplexed channel for an outgoing transmission in a network of switch elements interconnected by a series of communications paths. An availability table for maintaining the free/busy state of each channel on each switch port in the switch element is provided. Means are additionally provided for limiting the search of the availability table for the earliest available channel to certain desired switch ports and channels.

Channel allocation system for distributed digital switching network

This invention relates to a switch module for use in an asynchronous transfer mode (ATM) system incorporating a shared buffer memory where incoming data cells are stored and subsequently transferred to exit ports. An incoming data cell is stored at a vacant buffer memory address on an interleaved, word-by-word basis and the address is placed in an appropriate priority queue in the appropriate exit port for the data cell. When time is available for transmission from the exit port, the data cell corresponding to the address at the head of the highest priority queue is sent to the exit port and transmitted.

Shared buffer switching module

A conferencing device and method among terminals in a distributed digital telephone switching system is provided. The telephone switching system has a plurality of switching elements for interconnecting telephone units and telephone lines via communication links. A duplex path is set between each party in the conference and a designated bridge port. The speech from all the parties in the conference is summed and at the bridge port the sum is sent back to all engaged in the conference. As each party receives the sum, it subtracts its own speech data and therefore obtains the speech data from the other parties in the conference.

Conferencing system for distributed switching network

A communication switching system with distributed control processing is provided. The system includes a digital switching network having a modular array of intelligent digital switching elements each having processors and memory to set up communication paths for voice and data between the terminal module processors such as line cards and telephone units. Each addressable location in the system is assigned a logical address code (LAC). When a route is requested, a switch element processor interprets the destination LAC and selects a route through the switch toward the destination with each switch element in the communication path setting a route toward that destination. The switching network provides duplex paths for flexible communication. With such a duplex path speech is directed from a first terminal unit such as a telephone station and a second terminal unit such as a line card into a bridge port which sums the speech data from the two sources. The summed speech is then sent from the bridge port to the terminal units.

Distributed control switching network for multi-line telephone

The broadcast system of the switching network provides for the broadcast or multicast of interface switch status broadcasts and interface switch event broadcasts. An interface switch feature processor initiates a broadcast message made up of two bytes of data on a first channel, with particular command codes to identify the type of data contained within the broadcast message, paired with another two bytes of data in the same frame on a second channel. Broadcast messages are sent into the switching network in a non-broadcast manner until they reach the fold point of the switch network. From the fold point the broadcast messages are broadcast on every available broadcast channel directed out of the switch network towards the interface switches.

Broadcast system for distributed switching network

A virtual private line key telephone system is provided. The system includes a console including a plurality of line keys each associated with a party that can be reached via a switched trunk line. A look-up table means associates the line keys with the telephone numbers of the associated parties. A communication path is established from the console to one of the trunk lines. Signals are sent to the central office via the selected trunk line corresponding to the telephone number in the look-up table means associated with a line key that is actuated to place a calls. The telephone number of incoming calls are determined and compared with telephone numbers in the look-up table. Thereafter the line keys which are associated with the incoming calls are determined. The incoming call is coupled to the console when a line key associated with the incoming caller is actuated.

Key telephone system with virtual private lines

A telecommunication switching system includes a number of control circuits each of which is common to a plurality of line circuits and is coupled through time division multiplex links with two processor controlled interface circuits which are further coupled to a switching network. Line scanning information is processed in the control circuits to reduce the work load of the processor controlled interface circuits. Said line scanning information is then transmitted in the TDM links to the processor controlled interface circuits. The transmission priority among the control circuits is determined by a priority arrangement established for the system. A channel assignment controls the allocation of channels of the TDM links leading to parts of the line circuits.

Telecommunication switching system and priority arrangement used therein

An associative processor is described wherein an array of associative processing cells is configured to achieve variable length multiplication of numbers, such as binary two's complement numbers, under mask control. A configuration suitable for signal multiplication is described wherein the processing sequences in all cells are compatable, each to the other, whether the cells are at the edges or the middle of an array row, and regardless of the computational sequences required to be performed. An associative cell structure is described, including an improved arithmetic logic unit having separate carry and borrow save paths which may be enabled and active simultaneously or alternately.

Associative processor with variable length fast multiply capability

A uniformly manufacturable solid state modular distributed control for a digitally switched local or central office servicing an expandable number of subscribers is disclosed in which subscriber lines and trunks communicate through a standardized hardware interface to a group switch. The described system provides microprocessor control of each call, with software distributed in accordance with the class of service per line, without the limitations of centralized control systems, but expandable without adverse affect on existing software. Switching control signals are communicated to and from the subscriber subsets to the group switch over the same paths which couple the speech signals thereto, thereby eliminating cumbersome and expensive separate control paths. In accordance with a further aspect of the present invention, subscriber calls are divided into orginating and terminating call halves, under subscriber control and separated by the group switch, thereby eliminating undesired interaction therebetween to provide for simplified software requirements.

Distributed control for digital switching system

A distributed control digital switching system is described in which a plurality of subscriber lines and trunks are provided with a switched access to various processing functions shared over a plurality of time shared multiplexed lines. Each processor of a first group of processors is dedicated to a group of terminals such as subscriber lines or trunks, and communicate with processors in a second group to provide pooled processing functions to one or more of said groups of terminals through a digital switching matrix. Processors in the first group perform a first set of processing functions, such as path set up and processors of the second group perform a second set of processing functions, such as call control. A multistage switching network provides a modularly expandable digital group switch, the operation of which is controlled externally from the terminals to which it is connected, and provides rate synchronous, phase (bit) asynchronous interconnection among the terminals which are interfaced and switched. Each processor of the first group is time shared over a security block of lines or trunks providing hardware interface therebetween while each processor of the second group provides pooled functions for a plurality of security blocks of lines and trunks. All data, speech and control signals are coupled over common transmission paths.

Distributed control digital switching system

A distributed control digital switching network is configured as a group switch having a plurality of stages of multiport single sided switching elements for selectively interconnecting a plurality of input terminals via the transmission paths established through the network by path selection control signals which are multiplexed on common transmission links to and through the network together with digitally encoded data from the terminals on common transmission paths such that data is received phase asynchronously at each stage of the network and is either coupled to a higher order stage of the network or folded back through the network by reflection to interconnect terminals switched by the network. The single-sided switching elements are selectively operable as single-sided or multi-sided in accordance with their position in the network.

Expandable digital switching network

A telephone central office switching network and a basic switching element utilized therein is disclosed herein. The basic switch element has the capability of reflecting traffic entering any of the inlets thereto back to any other traffic inlet and the capability of connecting any of the inlets thereto to any of the outlets therefrom. The basic switch is implemented in the network incorporating the reflection technique, sometimes called a one-sided network in which the outlet from a switching stage is in a preferred embodiment connected to a higher order switching stage such that the outlets of the switching stages are progressively connected in a multistage configuration from the terminal stage into the folding point in increasing order, thereby enabling the outlets of the higher order stages to be used as reflection ports while simultaneously remaining available for connection to higher order switching stages without the necessity of recabling. A continuously expandable switching network is thus provided wherein incoming traffic penetrates the network only to the degree necessary to complete the required signal connection and is implementable either in space division configuration, time division configuration or any combination thereof, and utilizing either analog or digital encoding techniques.

Growing community of inventors

East Norwalk, CT, United States of America

John M Cotton