Avaya Inc.

Nortel Networks Corporation

Northern Telecom Limited

Andre M Cyr

John Cornelius Lynch

Zlatan Dedic

Ian B McPherson

Ayman Bedair

Thornton L Collins

Peter Tarle

David Ward

Glenn Eng

Michael Pothier

David Cairns

Metodej Valentik

Tod Allen Rikley

An adaptation mechanism monitors, maintains and controls quality of voice-grade for communications among end-systems in a distributed PBX topology, thereby providing an enhanced Quality of Service (QoS) for the network.

Adaptively maintaining quality of service (QoS) in distributed PBX networks

Systems and methods measure a round trip delay of voice packets through a telephone system that includes a plurality of cabinets connected through a network. Each cabinet includes a link for communicating with other cabinets through the network by passing information such as voice packets. Each link includes a field programmable gate array (FPGA) that inserts and reads information in the voice packets to measure a time delay of the network. A first cabinet link sets a transmit bit in a voice packet directed to a second cabinet and starts a timer. The second cabinet monitors the transmit bit in received voice packets to determine if the bit is set. If so, the second cabinet sets a receive bit in the next outgoing voice packet directed to the first cabinet. The first cabinet monitors the receive bit in incoming voice packets and if set, stops the timer. The resulting value in the timer reflects the network delay.

System and method for measuring round trip delay of voice packets in a telephone system

A system for re-establishing synchrony with data that was synchronous data in a source device but for which synchrony is lost when the data is transmitted over an asynchronous and unreliable medium to a destination device. The system includes buffering of the data received in the destination device from the asynchronous network, readout of the buffers according to a clock, and adjusting the rate of the clock in the destination device according to the rate of transmitting the data from the source device. The clock rate is thus adjusted to re-establish synchrony, and the clock may be used to control synchronous handling of the received data within the destination device.

System and method for synchronizing with data received over an unreliable asynchronous medium

A key telephone system (KTS) or a telephone private branch exchange (PBX) card is integrated into a personal computer to provide telephone system features. The telephone card includes a call controller, a switching network and an interface bus controller for coupling data signals between the PCI bus and an internal bus of the call controller whereby the telephone card is able to communicate with resources of the PC such as a LAN and a hard disk bulk memory for executing telecommunications functions. In this arrangement the PCI bus must carry both asynchronous data processing and control signals as well as reformatted synchronous signals. The addition of a synchronous bus for transporting synchronous signals is used to couple these signals between the switching network, a telephony features controller and the hard disk bulk memory. The use of the synchronous bus provides for improved telephone traffic capacity and PC functionality.

PC with telephony exchange function

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Belleville, Canada

Andre M Cyr