At&t Bell Laboratories

American Telephone and Telegraph, Co.

At&t Ipm Corp.

Lawrence Baranyai

John R Colton

Dominick Scordo

Thomas P Sosnowski

Michael S Lane

Nattu V Srinivasan

Francis H Butler

John C Cox

Chi H Lin

An upgrade arrangement wherein the switching functions of an in-service switch or cross-connect system are transferred or 're-homed' onto a new, larger capacity switch via the existing input and output ports of the original system. The re-homing can be performed without loss of service, even if the original system is operating at full-capacity. By exploiting the protection redundancy engineered into existing telecommunication switching systems, all of the signals being routed through the original switch are temporarily consolidated onto only one-half of the switching fabric normally required to accommodate such connectivity. This signal consolidation allows half of the original switch ports to be brought off-line (without a service disruption), and linked to the new, higher capacity switching fabric. The signals that had been consolidated within the original switching fabric are then re-routed onto the new switching fabric (via the linked ports), and the other half of the original switch ports are brought off-line and linked to the new switching fabric. The re-routed signals (still being switched in a consolidated format within the new switching fabric) are then redistributed (unconsolidated) among the linked ports and the new switching fabric so that a normal switching pattern is reestablished. Re-homing the signals onto a single new switching fabric allows all connections to be managed from a single control point. In addition, the re-homing to the new switching fabric is operationally transparent (timing and protocols within the switching system are unaffected, and full non-blocking access is maintained), and all existing cabling to and from the original input and output ports remains intact and functioning. In a preferred embodiment of the invention, the input and output ports of the original switching fabric are linked to the new switching fabric via electro/optic interfaces, which replace the standard input and output circuits of the original system.

In-service upgrade for a telecommunication system

A memory matrix for storing control words for controlling a common control time division multiplexed (TDM) switch is formed by employing a plurality of shift registers connected in recirculating configuration. Synchronization of control word time slots in the memory matrix to system timing is realized by storing a timing marker which is advanced in identical manner as the control word time slots. If synchronization between the system timing and control word time slots is interrupted, it is restored by controllably inhibiting advancing of the control word time slots and the stored timing marker.

Control memory using recirculating shift registers for a TDM switching

The disclosure relates to error/fault detection in signal processing systems such as those employed in a time division multiplex conferencer. The digital message samples (of the conferees) and the accompanying parity bits are delivered to a signal processor e.g., a binary arithmetic adder (10). The adder sums the message samples and this sum is coupled to a first parity tree (11), which in response thereto generates a first parity bit. The carries generated by the summing operation and coupled to a second parity tree (12) along with the message parity bits and the second parity tree generates a second parity bit therefrom. The first and second parity bits are compared (13) and if they differ a fault exists. Corrective action is taken immediately--the faulty conference 'leg' is removed from the conference connection without affecting the remaining legs in the conference or any other conference.

Fault detection arrangement for a digital conferencing system

A time division multiplex conferencer for continuously summing and outputting digital message samples received from n subscribers in n respective time slots. Message samples collected from each subscriber of a conference connection are summed during a first time frame and outputted during a second time frame. The conferencing is carried out in real time under common control to provide one or more conference-type connections between two or more subscribers. The conferencer also has the ability to establish transmit-only or receive-only connections for one or more subscribers. The conferencing is conducted in a manner that is completely independent of time slot assignments within a frame.

Time division multiplex conferencer

There is disclosed a general purpose linear time division multiplexed conference system for continuously summing and supplying digital message samples arriving in time slots within a frame. The conference system integrates both voice and data network conference connections and provides total isolation between the secondary legs of a data network connection. The host computer of a data conference connection is assigned to the lowest ordered time slot relative to the time slots assigned to secondary legs of the data conference connection. The summation of data samples accumulated from each leg of the data conference connection during a write cycle is modified during a next supply cycle after distribution to the host computer but prior to distribution to secondary legs. Modification is achieved by overwriting the summation with the data sample received from the host computer during the prior write cycle.

Linear time division multiplexed conferencer for data transfer

There is disclosed a linear time division multiplexed time slot conference for continuously summing and outputting digital message samples received from n connected telephone lines respective to m sequential time slots. The conferencer processes 256 time slots and uses prefetching techniques to reduce memory requirements to allow the circuit to be integrated into a single chip. Besides establishing conference-type connections, the conferencer has the capability to establish broadcast and monitor connections. Message samples collected from each connected line of a conference connection are summed during a first time frame and outputted during a second time frame. The conferencer includes circuitry for detecting either positive or negative overflow which could result from the summation process, and in this respect, selects an alternate message for outputting.

Growing community of inventors

Howell, NJ, United States of America

Lawrence Baranyai