Detail Of Line Circuit Or Line Card Patents (Class 379/166)
  • Patent number: 8531286
    Abstract: A security system includes at least one audio sensor and an alarm panel that transmits alarm report data through a communications network to at least one alarm receiver located at a central station remote from the premises that receives the alarm report data transmitted from the alarm panel through the communications network. A line card receives the alarm report data. An alarm receiver processor receives and processes regulated alarm report data in accordance with Underwriter Laboratories 1610 requirements. The line card is operable for receiving non-regulated alarm report data that is not regulated in accordance with Underwriter Laboratories 1610 requirements. The line card includes a secondary communications channel interfaced to a central station automation system and routes the regulated alarm report data to the central station automation system over the secondary communications channel and bypasses the alarm receiver processor.
    Type: Grant
    Filed: September 4, 2008
    Date of Patent: September 10, 2013
    Assignee: Stanley Convergent Security Solutions, Inc.
    Inventors: Gary Friar, Mark Davis
  • Patent number: 8364154
    Abstract: Communications over a network are selectively routed to one of multiple mobile devices identified by the same mobile device number. In one example, a method includes identifying a first mobile phone associated with a first activation priority by a phone number and identifying a second mobile phone associated with a second activation priority by the same phone number. The activation priority indicates a priority with which the first and the second mobile phones are activated for communications on a network. Communications associated with the phone number are selectively routed to one of the first mobile phone or the second mobile phone having a highest activation priority. The phone number defines an address at which the communications are routed to the one of the first mobile phone or the second mobile phone having the highest activation priority without being routed to an intervening address defined by another device number.
    Type: Grant
    Filed: November 16, 2010
    Date of Patent: January 29, 2013
    Assignee: Google Inc.
    Inventors: Mandayam Thondanur Raghunath, Nilesh Tathawadekar
  • Patent number: 7873160
    Abstract: Disclosed is a telephone to be installed in a house or an office and capable of effectively preventing leakage of data stored in or unauthorized use of the telephone. For this end, a security button 15 is provided for inhibiting the use of all or a part of the stored data in or functions of the telephone. The security button 15 enables the user to set the security condition by a single push-down operation or choose desired security levels by continuous operations. An LED may be installed in the security button 15 to emit light in different colors or patterns for respective security levels.
    Type: Grant
    Filed: September 12, 2008
    Date of Patent: January 18, 2011
    Assignee: NEC Infrontia Corporation
    Inventor: Daisuke Yumita
  • Patent number: 7729338
    Abstract: The invention is a provider agent product and method that operates as a software interface between a telephony card and a session manager in an advanced communications network. The provider agent receives event messages from the telephony card indicating on-hook events, off-hook events, and digit events. The provider agent instructs the telephony card to provide dial tone, ring current, ringback, and busy signals to the telephones. The provider agent also exchanges messages with a session manager in the network. These messages include: invite messages, reply messages, join messages, and terminate messages. In response to the above processing, the provider agent instructs the telephony card to interwork telephony signals on a telephony channel with ATM signals on an ATM virtual channel. The provider agent is comprised of a plurality of software objects that are stored on a software storage medium and that include: a controller object, port objects, and event objects.
    Type: Grant
    Filed: May 21, 2002
    Date of Patent: June 1, 2010
    Assignee: Sprint Communications Company L.P.
    Inventors: Abdullah Murat Bog, Steven Turner, Matthew Kung-Wei Jonathan Barrow, Tracey Mark Bernath
  • Patent number: 7697513
    Abstract: A method for sending messages between a first PBX device and a second PBX device is provided. The method includes receiving a first message from the first PBX at a first gateway. The message includes a standard section and a proprietary section. The standard and proprietary sections may be provided in a protocol associated with the PBX system. The standard section is decoded but the proprietary section is not. The standard section and proprietary section are then packetized in one or more packets. These packets are then sent over a packet-based network to a second gateway and may be routed over the packet-based network using the decoded standard section. The second gateway is then configured to generate a second message including the standard section and the proprietary section for sending to the second proprietary PBX device.
    Type: Grant
    Filed: July 29, 2005
    Date of Patent: April 13, 2010
    Assignee: Network Equipment Technologies, Inc.
    Inventor: Kevin Isacks
  • Patent number: 7536005
    Abstract: A ring detect circuit is shown that includes a regenerative latch configured to be coupled to a telephone line. The regenerative latch is configured to generate a fast transient signal in response to a ring signal on the telephone line. The latch is coupled to an isolation transformer through a capacitor. The fast transient passes across the capacitor and through the transformer. A comparator detects the fast transient and, responsive thereto, generates a ring detect signal.
    Type: Grant
    Filed: December 1, 2005
    Date of Patent: May 19, 2009
    Assignee: Silicon Laboratories, Inc.
    Inventors: Wayne T. Holcombe, Vitor Pereira, Tiago Marques
  • Patent number: 7330502
    Abstract: An input/output circuit includes a reference clock generator configured to generate a reference clock. A signal transmitter is configured to transmit serial data in synchronization with one of the reference clock and a test clock. A signal-receiving circuit is configured to receive the serial data, and to generate a converted signal from the serial data. A test circuit is configured to detect an error between each phase of the converted signal and the test clock when the signal transmitter operates in synchronization with the test clock.
    Type: Grant
    Filed: April 14, 2004
    Date of Patent: February 12, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yuuichi Hotta
  • Patent number: 7289615
    Abstract: A private branch exchange changes the load distribution according to the use condition by a main control unit and a sub-control unit. A line card comprises a first module group normally carrying out various operations in response to an instruction of the sub-control unit, a second module group carrying out various operations in response to the sub-control unit or the main control unit, a bus arbitration circuit, and an internal module bus selecting unit having a bypass selector for bypassing the bus arbitration circuit. The main control unit predicts the load on a system at the start of the system from the information stored in the incorporated line card, and determines, considering the prediction result, whether the control is made by the sub-control unit or the main control unit, for each module of each line card.
    Type: Grant
    Filed: January 9, 2002
    Date of Patent: October 30, 2007
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Kazunori Hayashi
  • Patent number: 7082125
    Abstract: A communication system is provided for transferring data through a digital switching network. The communication system includes a client modem, a linecard in communication with the client modem over a local loop, and a linecard modem interfacing with the linecard and the digital switching network. The client modem modulates client data to generate modulated client data for transmission to the linecard over the local loop, and the linecard modem receives the modulated client data from the linecard and demodulates the modulated client data to generate the client data for transmission through the digital switching network. Further, the linecard modem modulates network data from the digital switching network to generate modulated network data for transmission to the client modem over the local loop, and the client modem receives and demodulates the modulated network data to generate the network data.
    Type: Grant
    Filed: November 20, 2001
    Date of Patent: July 25, 2006
    Assignee: Mindspeed Technologies, Inc.
    Inventors: Jason B. Brent, Thomas C. Liau
  • Patent number: 7068758
    Abstract: A multi-services access platform is presented for supporting metallic test access in switching or multiplexing devices such as digital subscriber line access multiplexers (DSLAMs). The multi-services access platform includes a chassis within which a predetermined number of card slots are included. Each of the card slots includes a number of input/output ports. A backplane runs along the chassis and includes a metallic test access bus. The metallic test access bus is operable to selectively couple to one or more input/output ports within the line card slots of the chassis to establish one or more metallic test paths. A relay matrix may be used to provide the selective coupling for the metallic test access bus, and the flexibility provided by the configuration of the relay matrix supporting the metallic test access bus allows for a variety of different test access ports (TAPs) to be supported.
    Type: Grant
    Filed: October 23, 2000
    Date of Patent: June 27, 2006
    Assignee: Alcatel Canada Inc.
    Inventors: Donovan Wallace, Geoffrey Dickinson, Kanwaljeet Jawanda, Sven A. Seelemann, Robert Gillan
  • Patent number: 6870832
    Abstract: The invention is a provider agent product and method that operates as a software interface between a telephony card and a session manager in an advanced communications network. The provider agent receives event messages from the telephony card indicating on-hook events, off-hook events, and digit events. The provider agent instructs the telephony card to provide dial tone, ring current, ringback, and busy signals to the telephones. The provider agent also exchanges messages with a session manager in the network. These messages include: invite messages, reply messages, join messages, and terminate messages. In response to the above processing, the provider agent instructs the telephony card to interwork telephony signals on a telephony channel with ATM signals on an ATM virtual channel. The provider agent is comprised of a plurality of software objects that are stored on a software storage medium and that include: a controller object, port objects, and event objects.
    Type: Grant
    Filed: March 12, 2001
    Date of Patent: March 22, 2005
    Assignee: Sprint Communications Company L.P.
    Inventors: Abdullah Murat Bog, Steven Turner, Matthew Kung-Wei Jonathan Barrow, Tracey Mark Bernath
  • Patent number: 6807262
    Abstract: A switch based feature that allows subscribers to adjust their incoming or outgoing audio signal strength. The value of the transmit or receive pad values on the subscriber line card are adjusted to control the strength of the audio signal transmitted to, or received from, the network. The subscriber controls the feature by sending a hook flash to the switch, entering the DTMF keypad feature code and transmit or receive volume parameters, and then returning to the call.
    Type: Grant
    Filed: October 3, 2000
    Date of Patent: October 19, 2004
    Assignee: Lucent Technologies Inc.
    Inventor: Stuart O. Goldman
  • Patent number: 6807261
    Abstract: A clock generating circuit generates a clock of a rate corresponding to a Dch rate in response to a specification from the exterior. A counting circuit detects completion of reception of one frame by counting the clock number up to “11” at timing at which a start bit detecting circuit detects a start bit in a serial signal. An S/P converting circuit fetches a serial Dch signal bit by bit in synchronism with the clock, outputs the latest fetched 10 bits in a parallel form and latches eight bits of a real data portion among the output data into a latch circuit at the time when reception of one frame is completed. In parallel with the above operation, a parity calculating circuit and flag/interruption generating circuit set various flags and generate a reception completion interruption.
    Type: Grant
    Filed: August 28, 2001
    Date of Patent: October 19, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshiaki Takahashi, Toshiaki Tanaka, Takeshi Horiuchi
  • Patent number: 6760419
    Abstract: A method and system for interconnecting a telephone system and an intercom system. In one exemplary embodiment, telephone switchgear is connected to a telephone interface which provides separate voice transmit and receive channels. For example, an E&M tie line module can be utilized, which also includes E&M signaling connections for signaling an incoming intercom call to a telephone and for signaling an outgoing telephone call to an intercom. In this exemplary embodiment, an interface circuit is also provided to allow for signal level adjustment along the transmit and receive channels, such that the signal gain of the telephone system can differ from the signal gain of the intercom system. The interface circuit can include a controller which controls a switching device for selectively allowing communication along the transmit and receive channels during periods when communication is desired.
    Type: Grant
    Filed: October 12, 2000
    Date of Patent: July 6, 2004
    Assignee: E. F. Bavis & Associates, Inc.
    Inventors: Michael E. Brown, Kenneth J. Rensing
  • Patent number: 6738463
    Abstract: A telecommunications device including a plurality of splitter cards mounted within a chassis. The device also includes a circuit board and a plurality of card edge connectors for providing electrical connections between the splitter cards and the circuit board. The device further includes POTS connectors electrically connected to the card edge connectors by first tracings of the circuit board, LINE connectors electrically connected to the card edge connectors by second tracings of the circuit board, and DATA connectors electrically connected to the card edge connectors by third tracings of the circuit board. The POTS and LINE connectors are arranged in pairs with the POTS and LINE connectors of each pair being electrically connected to a common one of the card edge connectors. The POTS and LINE connectors of at least some of the pairs are inverted in orientation relative to one another.
    Type: Grant
    Filed: June 29, 2001
    Date of Patent: May 18, 2004
    Assignee: ADC Telecommunications, Inc.
    Inventor: Paul W. Schmokel
  • Publication number: 20040066923
    Abstract: A gateway 11 for using non-IP digital telephone handsets 10 with an IP call controller (“PBX”) 12, 24, 42. The gateway may be implemented to work with any non-IP digital telephone handset and any IP call controller. The call controller may be a public protocol IP Centrex call controller 24 or a proprietary protocol call controller 12, 42. The gateway is programmable so that a single hardware unit can be programmed after it is plugged in to work with any such devices. The programming is accomplished via IP download from a server on the global IP network 23. The gateway may be implemented as a plug in card 40 for an IP call controller 42 that accepts plug in cards. Alternatively, it may be implemented to work with remote IP call controllers 12, 42. In this latter configuration, the gateway may include a router for other IP devices which is designed to give voice quality preference to the telephone handsets over other IP devices.
    Type: Application
    Filed: June 27, 2003
    Publication date: April 8, 2004
    Applicant: CITEL Technologies LTD.
    Inventor: Michael J. Robinson
  • Patent number: 6681001
    Abstract: Computer integrated telecommunication systems are disclosed that provide a message exchange interface that transfers data and control requests generated by applications running on a computer system directly to a telecommunications unit that is adapted to respond to the data and control requests generated by these application programs. In particular, PBX systems are disclosed that include message exchange interfaces that provide fault tolerant operation and that directly map application programs running on a computer system into the controller element of the PBX system. Further systems are disclosed that provide message exchange interfaces that allow the efficient transfer of audio signals between a computer system and a telecommunication unit.
    Type: Grant
    Filed: August 10, 1998
    Date of Patent: January 20, 2004
    Assignee: Nortel Networks Limited
    Inventors: John B. Clayton, Michael J. Newman, Steven M. Staudaher
  • Patent number: 6668047
    Abstract: There is described a key telephone system which enables rewriting of the main program of the key telephone system, recovery of the key telephone system from a failure, and maintenance of the key telephone system such as diagnosis in an immediate, flexible, and inexpensive manner, a maintenance method for the key telephone system, and a medium on which is recorded a program for carrying out the maintenance method. A program to be rewritten is downloaded from an external device to a second storage means. After an existing program of a storage means has been saved into the second storage means, the downloaded program stored in the second storage means is transmitted and rewritten into the storage means. Failure information recording means records information regarding at least failures that occur at the time of downloading the program, failures that occur at the time of saving the existing program, and failures that occur at the time of rewriting the downloaded program.
    Type: Grant
    Filed: July 18, 2001
    Date of Patent: December 23, 2003
    Assignee: Matsushita Electric Industrial Co., ltd.
    Inventor: Takafumi Suzuki
  • Patent number: 6563924
    Abstract: A hybrid subscriber matching circuit for an electronic exchange which matches transmitted/received data so as to permit call communications between the exchange and subscribers. The subscriber matching circuit is constructed by individual parts without using a transformer or SLIC, and thus can simplify the peripheral parts thereof as well as strongly resist external impact.
    Type: Grant
    Filed: August 26, 1999
    Date of Patent: May 13, 2003
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Young-Ho Cho
  • Publication number: 20030002641
    Abstract: A telecommunications device including a plurality of splitter cards mounted within a chassis. The device also includes a circuit board and a plurality of card edge connectors for providing electrical connections between the splitter cards and the circuit board. The device further includes POTS connectors electrically connected to the card edge connectors by first tracings of the circuit board, LINE connectors electrically connected to the card edge connectors by second tracings of the circuit board, and DATA connectors electrically connected to the card edge connectors by third tracings of the circuit board. The POTS and LINE connectors are arranged in pairs with the POTS and LINE connectors of each pair being electrically connected to a common one of the card edge connectors. The POTS and LINE connectors of at least some of the pairs are inverted in orientation relative to one another.
    Type: Application
    Filed: June 29, 2001
    Publication date: January 2, 2003
    Applicant: ADC Telecommunications, Inc.
    Inventor: Paul W. Schmokel
  • Patent number: 6195423
    Abstract: A multi-line telephone switch device wherein relays added to a routing switch automatically route incoming calls on a plurality of lines to predetermined devices based upon the distinctive rings or tones present on the lines. A number of relays can be added to the routing switch. A line select relay connects the routing switch device to a specific incoming line. A bypass relay allows the device to connect a line directly to an extension by bypassing the routing switch. An invert relay enables the invention to reverse the designation and the routing priority of the incoming telephone lines. Ring detectors detect incoming rings and output a signal to a processor which then directs the switch configurations. Additionally, the system enables a single line telephone answering device to answer and record messages from a multitude of incoming lines. The multi-line telephone switch can uniquely route calls based upon the distinctive ring cadence on each of the lines.
    Type: Grant
    Filed: November 21, 1997
    Date of Patent: February 27, 2001
    Assignee: Command Communications, Inc.
    Inventors: Gary S. Smock, Charles E. Copeland
  • Patent number: 6128300
    Abstract: An apparatus and methods for communicating data over a voice-band communications loop are disclosed. The apparatus includes transceiver circuitry, a backplane interface, backplane interconnection circuitry, and signaling circuitry. The transceiver circuitry transmits and receives voice-band modulated data over the communications loop. The backplane interface provides for physical interconnection to the backplane. Backplane interconnection circuitry couples the transceiver circuitry and the backplane interface to each other for data transmission to enable the exchange of digital data between the transceiver and the backplane. The signaling circuitry transmits and receives POTS call control signals over the communications loop. A method for receiving voice-band data is disclosed.
    Type: Grant
    Filed: December 3, 1997
    Date of Patent: October 3, 2000
    Assignee: Nokia High Speed Access Products Inc.
    Inventor: Fred Horton
  • Patent number: 6115459
    Abstract: A telephone switching system 10 comprises a plurality of physical ports 20, and switches removable terminals based on predetermined connection information, wherein such connection information is arranged to be capable of being stored and rewritten in a RAM 60 by inputting from the terminal. When a physical port connecting to a terminal interface 30 is reconnected from a first terminal to a second terminal, a CPU 40 rewrites the connection information stored in the RAM 60 so that an extension number the user desires is stored for the physical port reconnected with the terminal.
    Type: Grant
    Filed: February 6, 1998
    Date of Patent: September 5, 2000
    Assignee: NEC Corporation
    Inventor: Kunihiko Wakabayashi
  • Patent number: 6046995
    Abstract: 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.
    Type: Grant
    Filed: May 26, 1998
    Date of Patent: April 4, 2000
    Assignee: Nortel Networks Corporation
    Inventors: Robert Turnbull, David Westergaard, Bruce W. Yee, Michael J. Lucas, Alan D. Eyre, Brian McKinney
  • Patent number: 5912957
    Abstract: A power failure shunting office line restoring circuit includes: a first relay having an office line tip port connected to a common port for connecting the tip port of the office line to a separate emergency telephone or a key telephone office line accommodating circuit in accordance with a first relay control signal; a second relay having an office line ring port connected to a common port for connecting the ring port of the office line to the emergency telephone or the key telephone office line accommodating circuit in accordance with a second relay control signal; a controller for generating the first and second relay control signals according to a power supply state or emergency telephone use state detection signal; first and second relay drivers for driving the first and second relays in accordance with the first and second relay control signals generated by the controller, and a detector connected to the first relay for detecting the use of the emergency telephone and for outputting the use state detect
    Type: Grant
    Filed: November 7, 1996
    Date of Patent: June 15, 1999
    Assignee: SamSung Electronics Co., Ltd.
    Inventor: Moon-Kyeong Park
  • Patent number: 5832071
    Abstract: An electronic patching system includes a first plurality of ports connected to the terminations of a plurality of telephone and data lines from the utility central office, and a second plurality of ports wired to a plurality of telecommunications devices. Both pluralities of ports are coupled to inputs of a controlled switching matrix, which connects each of the telecommunications devices to one or more of the telephone and data lines. The switching matrix is operated by a programmable logic array that directs the matrix to establish and maintain the desired connections between the telephone equipment and the telephone and data lines, computer network lines, and the like. The switching matrix includes a high voltage switch portion to handle analog telephone instruments. An algorithm for controlling the programmable logic array is created using a personal computer, and stored in memory.
    Type: Grant
    Filed: December 16, 1997
    Date of Patent: November 3, 1998
    Assignee: Voelker Technologies, Inc.
    Inventor: Joseph L. Voelker
  • Patent number: 5652788
    Abstract: One of the internal key telephone sets coupled to a key telephone apparatus capable of automatic call distribution operates as a supervisor and other operate as agents. Under the automatic call distribution, the statuses of the agents and their number are stored in a memory. The stored statuses of the agents are informed to the supervisor. Each key telephone set has a display unit. When one of the key telephone sets operates as the supervisor, the informed statuses and their number are displayed on the display unit of the supervisor. With identification data of a specific agent, the status of the specific agent is displayed on the display unit of the supervisor. To operate one of the key telephone sets as the supervisor and other the agents, first, a password is entered from one of the key telephone sets. The input password is compared with a first reference password for the supervisor and with a second reference password for the agents.
    Type: Grant
    Filed: May 17, 1996
    Date of Patent: July 29, 1997
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Masahiko Hara
  • Patent number: 5640448
    Abstract: Execution of guide simulation of the button operation is accompanied with the display of the button operation procedure and also the indication of the fact that a key telephone is actually used or a tone is being generated. The simulation state is first set by the button operation in one of many key telephone sets (1-1 to 1-m), and first control information is produced. A main control unit 10 sets an initial state of simulation in accordance with the first control information at a particular key telephone set which outputs the first control information. Second control information is then supplied to a main control unit 10 by pushing the operation button of the key telephone set, and display of the button operation procedure and indication of a lamp or generation of the tone, which are similarly created as a function is actually executed, are carried out in the key telephone set under control of the main control unit 10.
    Type: Grant
    Filed: February 9, 1996
    Date of Patent: June 17, 1997
    Assignee: NEC Corporation
    Inventor: Fumiyoshi Toyoshima
  • Patent number: 5513179
    Abstract: A line card (1) in a private branch exchange (1) accommodates interfaces (1) which switch standard output frames on a system bus. These standard output frames contain control data in addition to subscriber data. As a result, the system frame of the system bus (SB) is not filled efficiently. By switching only the subscriber data from the standard output frames to the system bus by the switching means, the system frame is filled efficiently.
    Type: Grant
    Filed: June 21, 1994
    Date of Patent: April 30, 1996
    Assignee: U. S. Philips Corporation
    Inventor: Rene Maas
  • Patent number: 5471523
    Abstract: The present invention provides a novel method and apparatus for interconnecting a telephone call and voice processing system ("CVPS") with a telephone key system control unit ("KSU"). A plurality of digital feature telephone ports of the KSU are connected to the CVPS. These connections provide two-way digital feature telephone call information and telephone audio paths between the CVPS and the KSU. The CVPS emulates digital feature telephones on each of these ports permitting the CVPS to automatically perform all of the functions available to a human user of one of the digital feature telephones. Optionally, interposed lines connected to telephone central office telephone lines may be used to provide some of the connections between the KSU and the CVPS.
    Type: Grant
    Filed: July 14, 1993
    Date of Patent: November 28, 1995
    Assignee: Voysys Corporation
    Inventors: Bernard J. Smith, David B. Seager, Raymond L. Tong, Thomas E. Rowley
  • Patent number: 5465256
    Abstract: A signalling pre-processor for receiving signalling from a line card of a telephone line. The pre-processor converting analog signalling into digital form and integrating the digital signal to remove noise spikes which would otherwise appear as false traffic. The system further includes bit packing for receiving digital signalling in the form of 8-bit bytes and forming 32 bit words, each 32 bit word containing the data from a single bit address of 32 of the 8-bit bytes. These 32-bit words are packed into a memory array until all bits of a given order for a time sample have been gathered. Signal processing is then performed on the 32 bit word to update a state machine for determining the signalling state of each telephone line.
    Type: Grant
    Filed: December 23, 1993
    Date of Patent: November 7, 1995
    Assignee: Krone AG
    Inventor: Charles J. C. Fowler
  • Patent number: 5388153
    Abstract: Telephone line status indication is improved by making measurements of the differential voltage across the Tip-Ring terminals of a telephone set. The telephone set is connected to a telephone line which is shared with other parallel-connected sets. The measurement of differential line voltage is made time the set changes state (i.e., between on-hook and off-hook). The maximum magnitude of one of the last three measurements is stored to represent the state, and is arithmetically averaged with the maximum magnitude of one or the last three stored for the oil-hook state to create a reference voltage. The reference voltage is updated each time the telephone set changes state and is continually compared with the present differential line voltage to determine which one is larger A light-emitting-diode on the telephone set indicates that the telephone line is in use whenever the reference voltage exceeds the measured differential line voltage.
    Type: Grant
    Filed: March 26, 1993
    Date of Patent: February 7, 1995
    Assignee: AT&T Corp.
    Inventors: Theodore O. Burger, John A. Karpicke, Donald M. Keen, Donald R. Means, Thomas A. Stahl, Brian A. Wittman
  • Patent number: 5224159
    Abstract: Disclosed is a key telephone system provided with a key service unit (KSU) 1 having a central control unit 6, and a digital key telephone set (DKT) 10 having a local control unit 13 for communications of control data with the central control unit 6. First and second add-on modules (ADMs) 24 and 34 for communications of control data with the central control unit 6 are optionally connectable to the DKT 10. When control data (up-data) are transmitted from the local control unit 13 of the DKT 10 to the KSU 1, a disable signal is given from the DKT 10 to the first ADM 24 to disable up-data from being transmitted from the first ADM 24. At this time, the first ADM 24 also outputs a disable signal to the second ADM 34 to disable up-data from being transmitted from the second ADM 34. At any selected time when no up-data are transmitted from the DKT 10, an enable signal is given from the DKT 10 to the first ADM 24.
    Type: Grant
    Filed: January 24, 1992
    Date of Patent: June 29, 1993
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Isaku Komuro
  • Patent number: 5151934
    Abstract: The present invention relates to a key telephone apparatus. In accordance with the present invention, a port for connecting terminal devices comprises two pairs having four wires, one pair having two wires of which is connected to a digital terminal device and the other pair having two wires of which is simultaneously connected to an analog terminal device, and there is provided switching control means for automatically selecting either of an interface circuit for analog terminal device and an interface circuit for digital terminal device connected to this port in accordance with the state of use of terminal devices. Therefore, it is possible to connect a one-pair two-wire analog terminal device and a one-pair two-wire digital terminal device together to one port and select either the interface circuit for analog terminal device or the interface circuit for digital terminal device according to the state of use of terminal devices under surveillance of the switching control means.
    Type: Grant
    Filed: September 13, 1991
    Date of Patent: September 29, 1992
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Takashi Hayashi
  • Patent number: 5097501
    Abstract: Apparatus is disclosed for use in a key set interface to overcome the incompatibility between key sets and tip and ring devices. The interface apparatus rejects ringing voltage and tip and ring loop current intended to be supplied on a first pair of conductors, the TR-pair. The interface further includes apparatus adapted for bi-directional communication of supervisory and control signals. In a preferred embodiment of the invention, a second pair of conductors, the service pair, transports bi-directional supervisory and control signals as well as operating power supplied by a key system controller for non-TR devices. Additionally, a transceiver adapted for sending and receiving voiceband information over the first pair of conductors is incorporated into the interface. An advantage of this key set interface is that operation of a key telephone set does not interfere with the operation of a tip and ring device bridged onto the first conductor pair.
    Type: Grant
    Filed: June 29, 1990
    Date of Patent: March 17, 1992
    Assignee: AT&T Bell Laboratories
    Inventor: Walter G. Kutzavitch
  • Patent number: 4953200
    Abstract: A private branch exchange for use with different types of telephone sets comprises a current detection device such as a photo-coupler for detecting a current flowing through a data line connecting to a multifunction telephone set to discriminate among different types of telephone sets and a current limiting circuit for limiting a current supplied from a power source device through a voice line in accordance with an detected output from said current detection device.
    Type: Grant
    Filed: April 25, 1989
    Date of Patent: August 28, 1990
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Hajime Yamasaki
  • Patent number: 4935957
    Abstract: A key telephone system has an oscillation preventing circuit comprising a termination impedance element, said circuit is a switching element and connected between the ground and another circuit which includes an impedance compensating circuit, therein. The switching element is turned ON upon oscillation of the impedance compensating circuit due to any remarkable impedance fluctuation in the signal transmission line, thereby effectively suppressing such oscillation of the impedance compensating circuit to maintain a favorable transmission efficiency.
    Type: Grant
    Filed: June 6, 1989
    Date of Patent: June 19, 1990
    Assignees: Nitsuko Limited, Nippon Telegraph and Telephone Corporation
    Inventors: Kinzi Tanaka, Kuniaki Shimoseki, Tetsuya Hiraji, Yoshiji Tanimoto, Minoru Okumura
  • Patent number: 4887293
    Abstract: A key telephone system comprised of a key service unit connected to a plurality of local sets via four-wire conductors for providing full duplex signal communication between the key service unit and sets. Signals are carried by a first pair of each of the conductors for unidirectional transmission of signals from each set to the key service unit, and the remaining pair of conductors carries signals transmitted by the key service unit for reception by one or more of the sets. Four-to-two wire signal conversion and line impedance balancing is effected by one or more trunk circuits of the key service unit in the event one or more of the local sets are connected via the key service unit for communication between the sets and the outside telephone lines.
    Type: Grant
    Filed: February 22, 1988
    Date of Patent: December 12, 1989
    Assignee: Mitel Corporation
    Inventor: Gerald Molnar
  • Patent number: 4796294
    Abstract: In an electronic telephone exchange and a method of connecting ports of the exchange, highways connected to a time switch is divided into extension highways and office line highways and thus highways are connected to discrete terminals of a connector formed with extension interface circuits and office line interface circuits. Input and output terminals are provided at positions corresponding to the discrete terminals so as to connect the extension interface circuits and the office line interface circuits to corresponding highways through the input and output terminals thereby effecting exchange of communication signals through the highways.
    Type: Grant
    Filed: December 2, 1987
    Date of Patent: January 3, 1989
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Kyoichi Nakagawara
  • Patent number: 4763354
    Abstract: A key telephone system comprising a key service unit and a plurality of key telephone sets is configured by this invention so as to permit use of IC cards which are adapted to admit user data for registration therein, to be inserted in any of the key telephone sets for the user data to be read out of the IC card, and to enable the user to utilize the key telephone set.
    Type: Grant
    Filed: May 28, 1987
    Date of Patent: August 9, 1988
    Assignee: Iwatsu Electric Co., Ltd.
    Inventors: Hiroshi Fukushima, Teruo Matsufuji
  • Patent number: 4759059
    Abstract: An interface circuit for interconnecting an analog telephone device with a digital telephone system includes an independent power supply (58) for driving the loop termination on an analog telephone device (22). An impedance matching circuit (54) and a summing network (42) are utilized to both couple the signal from the analog telephone device (22) to the analog input of a key service unit (10) and match the impedance therebetween. A switch, (46) is provided to disconnect the analog port of a digital telephone device (12) that is compatible with the key service unit (10). When the analog telephone device (22) is in the off-hook mode, a switch control (52) opens the switches (48) and (50) of switch (46). The digital telephone device (12) is under the control of a digital transmission line (20) to maintain an analog interconnection in the key service unit (10). The analog telephone device (22) operates on an independent loop termination with an independent loop current.
    Type: Grant
    Filed: June 1, 1984
    Date of Patent: July 19, 1988
    Inventor: Larry B. Christensen
  • Patent number: 4736409
    Abstract: A private branch exchange includes a common control module and a plurality of line/trunk modules. A plurality of line/trunk cards are contained in a respective line/trunk module and terminals of the same type, such as digital telephones or standard telephones, are connected to the respective cards. For control data transmission, the line/trunk cards of each of the line/trunk modules are coupled to the common control module via a common control data highway. Each line/trunk card includes, for terminal control, a central processor unit (CPU) and random access memory (RAM) for storing a control program in accordance with the type of terminals. To the line/trunk card is allocated an individual address and group address representing a group of line/trunk cards to which are connected terminals of the same type.
    Type: Grant
    Filed: September 2, 1986
    Date of Patent: April 5, 1988
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroyuki Hasegawa, Makoto Osada, Masakazu Shirakawa
  • Patent number: 4726060
    Abstract: A line circuit for driving a ringer and a service indicating lamp in a telephone set, including a high frequency transformer (T.sub.2), a switching circuit (22) for intermittently disconnecting a D.C. voltage applied to the primary winding of the transformer (T.sub.2), and a control signal generating circuit (23). The control signal generating circuit generates a first control signal having high frequency and having a first duty ratio when the ringer is to be rung; and generates a second control signal having the same frequency but having a second duty ratio smaller than the first duty ratio when the service indicating lamp is to be lit. The first or the second control signal is applied to the switching circuit so that the high frequency transformer generates a ringing signal or a D.C. voltage to light the lamp. Since the high-frequency transformer is commonly used for generating the ringing signal and the D.C. voltage for the lamp, the line circuit can be made small and light.
    Type: Grant
    Filed: December 27, 1985
    Date of Patent: February 16, 1988
    Assignee: Fujitsu Limited
    Inventors: Masaki Itoh, Junichi Koike, Yoshishige Tanaka
  • Patent number: 4691345
    Abstract: A two line telephone available for the home or the small business employs five pushbuttons for line selection, conference, hold and intercom. The line circuits and the conferencing switches are opto-isolated so that a single transformer coupled power supply is used. The usual illumination is provided in all of the pushbuttons to indicate that their function is being implemented. The conference function is implemented using the transformer coupled SCR circuit of U.S. Pat. No. 3,470,867.
    Type: Grant
    Filed: May 12, 1986
    Date of Patent: September 1, 1987
    Assignee: Rice Multiphones, Inc.
    Inventors: Richard J. McAlevey, Malcolm D. Muir, Johan S. van der Laan