Nortel Networks Corporation

Northern Telecom Limited

Westronic, Inc.

David Jeffrey Westergaard

Robert Barrie Turnbull

Alan D Eyre

Brian Clifford McKinney

Bruce W Yee

Michael J Lucas

Aaron James Bobick

Brian Lawrence Buckler

Timothy Augustus Kuechler

Kenneth J Caird

Eric W Godberson

Zygmunt Pasturczyk

A multi-line key telephone system not having a key service unit includes three analog telephone lines to which up to eight, three-line telephones may be connected to provide enhanced service features with cost-effectiveness. System reliability is maintained, notwithstanding a power dependency of the telephones, by including POTS telephones to provide uninterrupted essential telephone service in the event of a power outage. Both data and voice communications between two or more of the three-line telephones is achieved by converting an input digital bit stream from either a digital or analog source into a corresponding out-of-band binary FSK radio frequency output signal that is transceivingly communicated between the three-line telephones as data packets within a TDM frame. The out-of-band signal thus permits analog voice communications on the same line to proceed without interference. A telephone initiating a communications session acts as a master station, establishing inter-station communications synchronous at the frame level and asynchronous at the packet level. The called telephone functions as a slave station in a second time slot synchronized to a first time slot in the TDM frame received from the master. Temporary storage of data in firmware buffers and controlled timing at both the master and slave permits these stations to function within their respective TDM frame time slots.

Key telephone system without common control

A multi-line key telephone system not having a key service unit includes three analog telephone lines to which up to eight, three-line telephones may be connected to provide enhanced service features with cost-effectiveness. System reliability is maintained, notwithstanding the power dependency of the telephones, by including POTS telephones to provide uninterrupted essential telephone service in the event of a power outage. Both data and voice communications between two or more of the three-line telephones is achieved by converting an input digital bit stream from either a digital or analog source into a corresponding out-of-band binary FSK radio frequency output signal that is transceivingly communicated between the three-line telephones as data packets within a TDM frame. The out-of-band signal thus permits analog voice communications on the same line to proceed without interference. A telephone initiating a communications session acts as a master station, establishing inter-station communications synchronous at the frame level and asynchronous at the packet level. The called telephone functions as a slave station in a second time slot synchronized to a first time slot in the TDM frame received from the master. Temporary storage of data in firmware buffers and controlled timing at both the master and slave permits these stations to function within their respective TDM frame time slots.

A multi-line key telephone system not having a key service unit includes three analog telephone lines to which multiple telephone stations may be connected for enhanced communications between stations. Each station is connected by a modem to a single telephone line and includes a Universal Asynchronous Receiver Transmitter (UART) communicating with the modem, a microprocessor and a digital signal processor for effecting voice and data transfers and communicating time division multiplex protocol control to another telephone station on the same line. The UART includes a synchronizer with a master clock for defining positions of voice and data packets within a TDM frame having a predetermined data bit structure, and a receiver for acquiring a first valid packet header and start bit and issuing a sync pulse to adjust the master clock to conform to the timing of a new communication session. A receive data register in the UART temporarily stores data packets indexed to a first position within a TDM frame, and a receive voice buffer accumulates and temporarily stores voice packets indexed to a second position within the TDM frame. Transmitted data and voice packets are initially accumulated and stored as data and voice bytes in respective transmit data and voice registers of the UART from which the bytes are coupled to a transmitter for packetizing and subsequent transmission to the telephone line via the modem under control of the synchronizer.

An apparatus and method for remotely answering a door. The apparatus includes a switch, a telephone transmitter and an a telephone receiver positioned near the door. At least one telephone station is operable to place a telephone call to a remote telephone identified by a pre-determined telephone number. An interface detects actuation of the switch and signals the telephone station to place the telephone call in response to actuation of the switch and places the telephone transmitter and receiver in communication with the telephone to establish telephonic communication between the telephone transmitter and receiver and the remote telephone.

Remote answering of doorbell

An apparatus for muting communications subscriber equipment connected to a communications line includes a monitoring circuit for monitoring electrical conditions of the communications line, when the subscriber equipment is connected thereto. A disconnection circuit is provided for disconnecting the subscriber equipment from the communication line and a termination circuit is provided for terminating the communications line with a dummy termination when the subscriber equipment is disconnected, such that, the communications line appears to be terminated by the subscriber equipment. When the subscriber equipment is disconnected from the communications line a power supply circuit provides power to the subscriber equipment with the same electrical conditions as determined by the monitoring circuit prior to disconnecting the subscriber equipment.

Subscriber equipment muting method and apparatus

A circuit for use with a SCWID adjunct to remove A.C. in-band signaling tones from the voice path to a telephone apparatus serially connected to the adjunct. The A.C. signal component is carried on top of the D.C. voltage used to power the telephone. The circuit includes means to monitor the D.C. voltage level and to pass this voltage substantially unchanged to the telephone. The A.C. signal in the form of a FSK tone, received from the central office, is used by the adjunct to provide a subscriber with call feature information such as the identity of a calling party while the telephone is off-hook.

Method and apparatus for removing FSK in-band signaling

An improved distribution automation remote terminal unit which directly connects to a distribution feeder. The distribution automation remote terminal unit of the present invention is directly connected to voltage and current sensors on the feeder to sense the presence of signals on the distribution feeder. The remote terminal unit includes the first transformer interconnected to the potential sensors to produce a potential signal of reduced peak-to-peak voltage corresponding in phase to the AC potential waveform on the distribution feeder. A second transformer is directly coupled to the current sensor for producing a current signal of reduced peak-to-peak voltage corresponding in phase to only the AC current waveform on the distribution feeder. The reduced peak-to-peak voltage signals are delivered into a multiplexer and are sampled a predetermined number of times. The sampled analog voltage is then digitized by a digital to analog converter and delivered into a digital signal processor. Waveform parameters are determined. A microcontroller then accesses the waveform parameters to determine information such as the operation of upstream and downstream devices on the distribution feeder. This information is selectively transmitted to a remote master station over a communications link.

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Calgary, Canada

David Jeffrey Westergaard