With Generating Of Call Associated Substation Signal Patents (Class 379/251)
  • Patent number: 8744060
    Abstract: Multiple instances of an incoming call in a unified communication system capable of communicating through multiple networks are provided to devices and/or applications associated with the called party. Upon acceptance or a global rejection of the incoming call through one of the end devices/applications, the remainder are provided a cancellation notice for the forked call request that includes information associated with which end device took the action, what type of action was taken, whether the action was based on automatic policy implementation.
    Type: Grant
    Filed: March 12, 2012
    Date of Patent: June 3, 2014
    Assignee: Microsoft Corporation
    Inventors: Rajesh Ramanathan, Pradipta Kumar Basu, Paul Tidwell, Srivatsa Srinivasan
  • Patent number: 8442206
    Abstract: A system and method of responding to an incoming voice call are described. The method may comprise receiving the incoming call at a voice communication device, monitoring a user input via the voice communication device and generating a user control signal in response to the user input. The user control signal may identify that termination of ring functionality associated with the incoming call is at least to be delayed. Further, a system and method are described of processing a voice call to a voice communication device. The method may comprise communicating the voice call to a voice communication device and receiving from the voice communication device a user control signal in response to a user input. Termination of ring functionality may be at least delayed in response to the user control signal. The invention extends to a device to process a voice call to a voice communication device.
    Type: Grant
    Filed: August 22, 2006
    Date of Patent: May 14, 2013
    Assignee: Cisco Technology, Inc.
    Inventors: Joseph Khouri, Labhesh Patel, Mukul Jain, Sanjeev Kumar
  • Patent number: 8320530
    Abstract: A method for realizing a multimedia call includes the following steps. A call request initiated by a calling terminal is received. An indication of the multimedia negotiation capability of the calling terminal is acquired, in which the indication of the multimedia negotiation capability identifies whether the terminal has the capability of supporting multiple multimedia negotiations or not. It is determined, according to the indication of the multimedia negotiation capability, whether the calling terminal has the capability of supporting multiple multimedia negotiations or not. A multimedia call connection is performed according to the multimedia negotiation capability of the calling terminal. It is determined, according to the factor whether the calling terminal has the capability of supporting multiple multimedia negotiations or not, how to perform the multimedia call connection, so as to flexibly realize the multimedia call connection accordingly.
    Type: Grant
    Filed: May 4, 2009
    Date of Patent: November 27, 2012
    Assignee: Huawei Technologies Co., Ltd.
    Inventors: Sichen Wang, Hui Huang, Peng Wang
  • Patent number: 8275114
    Abstract: A method and a system for implementing ring back tones and ring back images in the VP service provides quality-assured and customized ring back tones and ring back images. A control module plays the ring back tones and ring back images for calling UEs through a voice and image channel defined in the VP series of protocols by resolving or pre-negotiating the voice and image coding formats supported by the calling UEs.
    Type: Grant
    Filed: March 13, 2006
    Date of Patent: September 25, 2012
    Assignee: Huawei Technologies Co., Ltd.
    Inventor: Haitao Jiang
  • Publication number: 20120213355
    Abstract: A telephone incoming call control unit 21B of a communication apparatus B 20B counts the total number of incoming calls and the number of incoming calls for each communication type indicating the breakdown of incoming call operations, as incoming call history data 21B for each telephone terminal B 30B as a slave unit, retrieves the incoming call history data 21B upon arrival of an incoming call from a certain calling party for the telephone terminal B 30B, extracts incoming call history data on the calling party from which the telephone terminal has received the incoming call, transmits the data to the telephone terminal when the telephone terminal is in an idle state, and causes an indicator 31B of the telephone terminal to display the data. The telephone incoming call control unit 21B thereafter transmits the call signal to the telephone terminal.
    Type: Application
    Filed: November 4, 2010
    Publication date: August 23, 2012
    Applicant: NEC Infrontia Corporation
    Inventor: Naoko Ishibe
  • Publication number: 20110311039
    Abstract: A method, a system and a device for call processing are disclosed in the embodiments of the present invention. The method includes: obtaining, by a call initiator, address information of all or part of call managers in a network domain that processes a call, where the all or part of the call managers include a call manager that processes the call and is adjacent to the call initiator; sending, by the call initiator, a first call creating request message to an adjacent call manager according to the address information of the all or part of the call managers; and receiving, by the call initiator, a first call creating response message from the adjacent call manager. In the case that a service at a client side is required to be sent through multiple networks at a server side, inter-domain link selection and admission control may be implemented through section call processing.
    Type: Application
    Filed: August 26, 2011
    Publication date: December 22, 2011
    Applicant: Huawei Technologies Co., Ltd.
    Inventors: Xiaobing Zi, Fatai Zhang
  • Patent number: 8036347
    Abstract: A method, apparatus and computer program product for providing additional information to an Interactive Voice Response (IVR) system user is presented. A call from a user is received at the IVR system, and a session is provided for the user. Additionally, a page is generated for the session. The page is communicated to the user; and is dynamically updated for the user as the user traverses menus of the IVR system.
    Type: Grant
    Filed: October 18, 2006
    Date of Patent: October 11, 2011
    Assignee: Avaya Inc.
    Inventor: Rajesh Kanade
  • Patent number: 7664253
    Abstract: A main terminal and a method of operating the same. In this method of operating the main terminal, the main terminal is connected to a telephone network so as to communicate with the telephone network, and selectively connects an external terminal to the telephone network. To perform the method, first, if it is requested that the telephone network be disconnected from the external terminal and instead be connected to the main terminal, an internal current to flow into the main terminal is obtained from a loop voltage generated when the external terminal is in connection with the telephone network. Next, the internal current is applied to the main terminal. Thereafter, the telephone network is disconnected from the external terminal and instead connected to the main terminal. While the internal current is flowing in the main terminal, the main terminal maintains the loop voltage generated when the external terminal is in connection with the telephone network.
    Type: Grant
    Filed: February 3, 2004
    Date of Patent: February 16, 2010
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Eog-kyu Kim
  • Patent number: 7587040
    Abstract: Systems and methods for detecting false signals on a telephone line. The devices provide an additional verification for outbound calls which result in a disconnected or not in service signal that such signals are valid and not false tones being emitted by a device or service employed by the call recipient, The type of additional verification of the outbound call is dependent on the telephone network on which the outbound call is placed. For example, on an analog telephone network a drop in loop current may be detected indicting a connected call which is contrary to the disconnected or not in service signals being received. Such connected signals can be detected on digital networks by monitoring dedicated control data channels or through the use of data received through the use of in-band signaling.
    Type: Grant
    Filed: November 30, 2005
    Date of Patent: September 8, 2009
    Assignee: Noble Systems Corporation
    Inventor: James K. Noble, Jr.
  • Patent number: 7587031
    Abstract: The present invention provides a technique for providing a forced hold service such as is used for an emergency services call, which is supported at least in part over a packet network. The forced hold service acts to effectively hold a connection for the call with a called party, even when the caller takes an action that would normally end a call, such as going on hook, pressing end, or the like. When the caller takes an action that would normally end the call, the forced hold service allows the caller to automatically reconnect to the emergency services provider over the held connection upon going offhook, pressing send, or the like. Alternatively, the emergency services provider can effectively re-engage the call wherein the caller is reconnected over the held connection upon going offhook, pressing send, or the like.
    Type: Grant
    Filed: December 22, 2005
    Date of Patent: September 8, 2009
    Assignee: Nortel Networks Limited
    Inventors: David P. Ress, William D. Gentry, Brian Stucker, Olga Wagner
  • Publication number: 20080240402
    Abstract: In a CTI system, when a wireless terminal is called in response to a transmission request from a personal computer, a key telephone main unit adds to a call signal identification information indicating that a call is based on the transmission request from the personal computer. When the call is received, the wireless terminal judges whether or not the identification information is added to the call signal (step S42). When it is judged that the identification information is added, the wireless terminal automatically answers the call (step S43). Otherwise, the wireless terminal does not automatically answer. Thus, in case of transmission from a CTI application, operability and convenience are improved.
    Type: Application
    Filed: March 27, 2008
    Publication date: October 2, 2008
    Inventor: Nobuo NISHIDE
  • Patent number: 7257222
    Abstract: The present invention relates to a ring voltage generation circuit for generating a ring voltage (VTR) between a TIP lead (9) and a RING lead (10) with minimized power loss for electronic subscriber circuits, comprising: a) an amplifier circuit (2) which receives an input voltage (VI) for amplifying the input voltage (VI) to provide the ring voltage (VTR); b) an absolute value generator (3) which receives the input voltage (VI), measures an absolute value (|VI|) of the input voltage (VI) and outputs the measured absolute value (|VI|) of the input voltage (VI); c) a DC/DC converter (4) which receives the measured absolute value (|VI|) of the input voltage (VI) and converts the measured absolute value (|VI|) of the input voltage (VI) into a supply voltage (VSUPPLY) for the amplifier circuit (2); and d) a common mode feedback device (5) which receives the supply voltage (VSUPPLY), a TIP potential (VT) of the TIP lead (9) and a RING potential (VR) of the RING lead (10) and which generates thereof a control volt
    Type: Grant
    Filed: August 2, 2004
    Date of Patent: August 14, 2007
    Assignee: Infineon Technologies AG
    Inventors: Bernhard Zojer, Joachim Pichler, Maria Giovanna Lagiola
  • Patent number: 7046755
    Abstract: A digital direct access arrangement (DAA) circuitry may be used to terminate the telephone connections at the user's end that provides a communication path for signals to and from the phone lines. Briefly described, the DAA provides a programmable means for the DC termination for a variety of international phone standards. The invention may also be utilized with means for transmitting and receiving a signal across a capacitive isolation barrier. More particularly, a DC holding circuit is provided in which a programmable DC current limiting mode is available. In the current limiting mode, power may be dissipated in devices external to a DAA integrated circuit. Moreover, much of the power may be dissipated in external passive devices, such as resistors.
    Type: Grant
    Filed: October 3, 2003
    Date of Patent: May 16, 2006
    Assignee: Silicon Laboratories Inc.
    Inventors: Timothy J. Dupuis, George Tyson Tuttle, Jeffrey W. Scott, Navdeep S. Sooch, David R. Welland
  • Patent number: 6917681
    Abstract: A power management circuit for a remote access platform extracts power from a wireline for powering a ring generator that generates a ringing voltage signal that is distributed to a plurality of subscriber circuits. A power-limited voltage converter steps up the wireline voltage to a higher ‘isolating’ voltage, charging a capacitor coupled to the ring generator. A monitor circuit reduces the power that the power-limited voltage converter can draw, if the wireline voltage drops too low. This prevents the wireline voltage from collapsing should the remote terminal be deployed at a distance from wireline voltage source (the central office) greater than its specified capability.
    Type: Grant
    Filed: April 1, 2002
    Date of Patent: July 12, 2005
    Assignee: Adtran, Inc.
    Inventors: Steven M. Robinson, Ralph R. Boudreaux, Jr., John S. McGary, John B. Wilkes, Jr.
  • Patent number: 6714644
    Abstract: An apparatus and method for supporting enhanced ring scheduling for devices on platforms with limited power supply while seeking to preserve caller ID information and normal ringing cadence is disclosed. The ring scheduling apparatus includes a “Line Manager” coupled to a “Ring Scheduler”. The Line manager monitors the signaling events and determines whether the signaling commands associated with the signaling events should be modified to indicate ringing, no ringing, or pass the signaling commands unmodified. The “Ring Scheduler” manages the available resources according to a ring cadence schedule so that the power supply of the device is not exceeded.
    Type: Grant
    Filed: December 13, 2000
    Date of Patent: March 30, 2004
    Assignee: Cisco Technology, Inc.
    Inventors: Jonathan Cohn, Somnath Mitra
  • Patent number: 6697482
    Abstract: Method and system for transmitting messages to subscribers of a telephone network during the set-up stage of incoming calls prior to the off-hook from a local exchange to at least one telephone terminal through an access system. The access system simulates, on one hand, the operation of a telephone terminal towards the local switching exchange such that it receives, from the local switching exchange and by means of an access node located in the access system, a first message preferably modulated and demodulates and stores it for subsequent replication; and, on the other hand, simulates the operation of a local switching exchange towards the telephone terminal such that it generates and transmits to the telephone terminal and by means of a network termination located in the access system, a second message preferably modulated which is a replication of the first message.
    Type: Grant
    Filed: November 19, 1999
    Date of Patent: February 24, 2004
    Assignee: Alcatel
    Inventors: Jose Luis Martinez Acedo, Juan Carlos De Las Heras Diez
  • Patent number: 6671370
    Abstract: A telephone system includes a plurality of telephone terminals wherein a call that is placed from a calling telephone terminal to a receiving telephone terminal is announced by activating a standard ringing indication at the receiving telephone terminal. A data file is provided having a plurality of different ringing indications therein. These ringing indications include a plurality of sound information that are both different from each other and different from a standard ringing tone, and a plurality of different visual information. When a call is placed from a calling telephone terminal to a receiving telephone terminal, the user at the calling telephone terminal may optionally elect to announce the call at the receiving-telephone-terminal using ringing indication that is selected from the data-file, for example sound information that indicates the identity of the calling-users, and/or visual information that indicates the priority of the call.
    Type: Grant
    Filed: December 21, 1999
    Date of Patent: December 30, 2003
    Assignee: Nokia Corporation
    Inventors: Eeva-Liisa Heinonen, Jaakko Itävaara, Heidi Karves, Kai Kronström, Kari Lehtinen, Jari Mononen, Petri Nykänen, Mikko Virtanen
  • Publication number: 20030076944
    Abstract: According to the inventive method, an incoming call that is directed to a subscriber terminal (Tln1) allocated to a subscriber group (Tln1 to Tln n) is signaled to the subscriber terminal (Tln1) called and additionally to at least one subscriber terminal (Tln A3 to Tln An) that is located outside the signaling transmission range of the subscriber terminal called.
    Type: Application
    Filed: October 15, 2002
    Publication date: April 24, 2003
    Inventors: Axel Kreten, Holger Prange
  • Publication number: 20030076942
    Abstract: The invention relates to a method for signaling and processing incoming calls for a call center. The invention further relates to a corresponding exchange and a corresponding call center. According to the invention, incoming calls for the call center and the subscriber numbers of the callers are signaled to the call center by the exchange via an Internet protocol link between the exchange and the call center.
    Type: Application
    Filed: October 15, 2002
    Publication date: April 24, 2003
    Inventor: Markus Boehm
  • Patent number: 6522668
    Abstract: A system and method are provided for special signaling with customer premises equipment. The system includes loop termination equipment coupled to a local loop and comprising a signal generator. The system also includes customer premises equipment coupled to the local loop. The customer premises equipment and loop termination equipment are operable to communicate across a communication link established on the local loop. The loop termination equipment is further operable to control characteristics of a signal generated by the signal generator and to provide the signal to the customer premises equipment as special signaling where the signal has a frequency that does not substantially interfere with voice traffic on the local loop. The special signaling can be used to implement enhanced service to the customer premises including busy signal, queued data request processing, push data and telephony services.
    Type: Grant
    Filed: November 30, 1998
    Date of Patent: February 18, 2003
    Assignee: Cisco Technology, Inc.
    Inventors: Gregory L. Singleton, Andrew M. Spooner, Ramona L. Boyd, Jason F McCullough
  • Patent number: 6088440
    Abstract: A telephone exchange transmits audible signals to a subscriber line to indicate exchange or network conditions. The audible signals to be transmitted to the subscriber line are selected from one or more available audible signal sources according to the contents of a store location for that subscriber line. Further store locations are provided for each subscriber line to enable selection of further audible signal sources dependent upon the condition. The subscriber may alter the contents of his or her store location by dialing a special code.
    Type: Grant
    Filed: January 15, 1998
    Date of Patent: July 11, 2000
    Assignee: British Telecommunications Public Limited Company
    Inventors: Paul C Millar, Robert BP Carpenter
  • Patent number: 5949873
    Abstract: A method of operating a communication switching system in conjunction with a PBX comprising: storing at the PBX equipment station identifiers in association with directory numbers, storing at the switching system the station identifiers in conjunction with the directory numbers and a PBX identifier, in the event of a station connected to the PBX going offhook, looking up at the PBX a station identifier associated with a directory number assigned to the offhook station, transmitting the looked up station identifier to the switching system, and upon receiving the transmitted station identifier at the switching system, looking up the corresponding directory number, and changing characteristics of a line between the switching system and the PBX over which communication is to take place, to suit predetermined characteristics based on the corresponding directory number.
    Type: Grant
    Filed: April 7, 1997
    Date of Patent: September 7, 1999
    Assignee: Mitel Corporation
    Inventor: Deborah L. Pinard
  • Patent number: 5920610
    Abstract: A telephone number status is rapidly and easily examined to update a telephone number list. Telephone numbers stored in a telephone number list are sequentially transmitted from an ISDN line to a telephone line in a digital communication mode for making calls, and the status of each called telephone line is determined from connection information or from a line disconnect reason received from an associated station.
    Type: Grant
    Filed: January 31, 1997
    Date of Patent: July 6, 1999
    Assignees: Synform Co., Ltd., Arasat Corporation
    Inventors: Atsushi Arami, Hiroshi Satoh
  • Patent number: 5881147
    Abstract: A technique for selectively storing as a selected ring one of various rings programmed in a ROM within a controller of a telephone which has a controller for storing a program for various rings therein, an output key for confirming the stored rings, and a selection key for selecting a ring, the technique including the steps of: storing as a selected ring one of the rings stored in the controller; and transmitting the selected ring stored in step in response to a call signal being inputted.
    Type: Grant
    Filed: October 10, 1996
    Date of Patent: March 9, 1999
    Assignee: SamSung Electronics Co., Ltd.
    Inventor: Jong-Kwang Kim
  • Patent number: 5699419
    Abstract: A keyset that connects to telephone switches via analog lines, wherein a processor in the keyset communicates with the switch via in-band signaling to provide keyset functionary. When a call comes into the switch for one of the directory numbers (DNs) associated with the keyset, the switch sends a frequency shift key (FSK) encoded message to all of the keysets associated with that DN. The FSK message includes at least the DN of the terminating telephone line, and may also include an extension number or other code. The processor in the keysets receives the message, decodes it, and then alerts the users of the incoming call.
    Type: Grant
    Filed: December 20, 1994
    Date of Patent: December 16, 1997
    Assignee: Lucent Technologies Inc.
    Inventor: Menachem Tsur Ardon
  • Patent number: 5655012
    Abstract: In a private branch exchange apparatus having a plurality of extension ports, each extension port capable of connecting a push button telephone and a general standard type telephone in parallel, when a call occurs at one extension port where the parallel connection has been done, a ring sound can be produced at the push button or standard type telephone selectively. An additional dialling provides the selection between the push button and the standard type telephone. A memory may specify either of the push button or standard type telephone to be ringed. A call between the push button telephone and the standard type telephone can be provided in accordance with the additional dialing or data stored in a memory.
    Type: Grant
    Filed: August 1, 1995
    Date of Patent: August 5, 1997
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kousuke Tsuchida, Sadaka Mitsuo
  • Patent number: 5627884
    Abstract: Caller information is automatically taken from a caller on hold, the call disconnected and the call returned at the time when the caller would have been serviced had the caller stayed on hold. The caller's number is verified and either DTMF or verbal extension information is used to reconnect the call.
    Type: Grant
    Filed: June 26, 1995
    Date of Patent: May 6, 1997
    Inventors: Mark J. Williams, Gregory A. Nightingale, Todd A. Randolph
  • Patent number: 5579386
    Abstract: An alerting cadence control system for a telephone network having a telephone exchange, subscriber transmission equipment connected to the telephone exchange, and a plurality of telephone sets each connected to the subscriber transmission equipment. The subscriber transmission equipment includes a plurality of subscriber interface cards and subscriber-shared alerting cadence control means, each of the cards incorporating a switch for performing alerting cadence switching of each telephone set. The subscriber-shared alerting cadence control means has a memory for control setting data in the format of a table in which is written a control program for controlling the switch connected to each telephone set. Where alerting cadence control is to cover a new subscriber service offered to a new telephone set, the applicable data in the table are modified from the telephone exchange under remote control without replacement of the subscriber interface card for that telephone set.
    Type: Grant
    Filed: April 26, 1995
    Date of Patent: November 26, 1996
    Assignee: Fujitsu Limited
    Inventor: Eiji Koda
  • Patent number: 5544235
    Abstract: A telecommunication network having a switching system connected to a called station by a line that provides notification to a called party of information relating to an incoming call. This information generally consists of the called number, but may also include an extension or other code. The called party identification is delivered to the called telephone station set during the silent period after ringing, or, advantageously, before ringing starts. A signal (e.g., FSK) is sent to the called telephone station set shortly before the ringing signal is sent to the called station. A converter at the customer premises receives the FSK signal and demodulates it. A control unit connected to the converter then causes the called DN to be displayed, may cause a distinctive ring to be made, or take other action depending upon its program.
    Type: Grant
    Filed: November 23, 1994
    Date of Patent: August 6, 1996
    Assignee: AT&T Corp.
    Inventor: Menachem T. Ardon
  • Patent number: 5490214
    Abstract: An improvement to a telephone system (10) having a first signal generator (21) which outputs a control signal only when it receives a certain request signal generated by the telephone system's client telephone (12). The invention contemplates a method and apparatus to generate a desired control signal when a request signal incapable of activating the first signal generator is produced by a client telephone (12).
    Type: Grant
    Filed: July 8, 1994
    Date of Patent: February 6, 1996
    Assignee: Voice Technologies Group, Inc.
    Inventors: David M. Straitiff, Robert R. Drzewiecki
  • Patent number: 5452345
    Abstract: An apparatus for controlling the magnitude of a metering signal used in a communication system includes a high pass filter and a threshold detector. The apparatus is preferably integrated on to a subscriber line audio-processing circuit (SLAC device) which is used on a line card. The device is operable with either 12 kHz of 16 kHz metering signals. The high pass filter preferably includes a shift register and an adder. The level detector preferably includes a shift register, an OR gate and an AND gate. The device preferably is utilized to reduce the echo or reflection caused by the variable impedance of subscriber lines in telephone communication systems.
    Type: Grant
    Filed: January 21, 1994
    Date of Patent: September 19, 1995
    Assignee: Advanced Micro Devices
    Inventors: Yan Zhou, Merle L. Miller, V. Vijayakumaran Nair, Sergio Ramirez
  • Patent number: 5406623
    Abstract: A telephone ringing arrangement where a non-sinusoidal ringing voltage waveform is used that has significantly longer intervals during which the waveform is near zero as compared to a sinusoidal waveform. A connect interval is defined as the time during which the magnitude of the non-sinusoidal ringing voltage waveform remains less than a predefined threshold. The connect interval includes a zero-crossing of the ringing voltage waveform. For an illustrative ringing voltage waveform, the zero-crossing has zero slope. A ringing relay is controlled to connect the non-sinusoidal waveform to a telephone line such that the connection time, including relay bounce time, occurs only during one of the connect intervals. Similar principles may be used based on a disconnect interval of the ringing current waveform, to reduce transients on disconnection.
    Type: Grant
    Filed: April 23, 1993
    Date of Patent: April 11, 1995
    Assignee: AT&T Corp.
    Inventor: Jeffrey A. Rovik
  • Patent number: 5335271
    Abstract: A ring trip detection circuit detects an OFF-hooked state of a telephone receiver during ringing of a telephone set by detecting a change in a voltage across two terminals of a transmission resistor through which a ringing signal is supplied to the telephone set from a ringing signal source.
    Type: Grant
    Filed: September 3, 1992
    Date of Patent: August 2, 1994
    Assignee: Fujitsu Limited
    Inventors: Kenji Takato, Kazumi Kinoshita, Kiyoshi Kurosaki, Taichi Kosako, Kazuyuki Minohara
  • Patent number: 5335270
    Abstract: A bell signal generating circuit for a key telephone set. A dc component of a pulse signal is removed by a photo-coupler to generate a first signal. A high frequency component of the first signal is removed by a filter to generate a second signal. A differential amplifier amplifies the second signal to generate a bell signal. To the differential amplifier, a dc supply voltage based on the dc signal in synchronism when the pulse signal is applied.
    Type: Grant
    Filed: August 19, 1993
    Date of Patent: August 2, 1994
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masayuki Tsurusaki, Takashi Watanabe
  • Patent number: 5172407
    Abstract: A circuit (4) for generating metering pulses (P) includes a multiplier circuit (MULT), a bandpass filter (BF), a comparison circuit (COMP) and a ramp signal generator (RAMP). A current (IC) from the ramp signal generator is multiplied (MULT) by an alternating voltage (VTXX) such as to form the metering pulse (P), which is transmitted, together with a speech signal (SP), to a subscriber (1) for registration. The output voltage (UF) of the bandpass filter (BF) is compared with a reference voltage (UR) in the comparison circuit (COMP). The output (9a) of the comparison circuit is electrically conductive only when the filter voltage (UF) exceeds the reference voltage (UR). When control signals (D) open a switch (SW), a capacitor (C1) is charged by a first current generator (10). The capacitor voltage (VC) incresases linearly and controls proportionally the current (IC) of the ramp signal generator (RAMP).
    Type: Grant
    Filed: October 9, 1991
    Date of Patent: December 15, 1992
    Assignee: Telefonaktiebolaget L M Ericsson
    Inventor: Hans Alenius
  • Patent number: 4995111
    Abstract: An improved ring trip circuit for a subscriber telephone, for detecting an on-hook state or an off-hook state of the telephone. The ring trip circuit can be formed in a small size and can be formed by a LSI. The ring trip circuit includes a voltage detecting circuit (2), for detecting a voltage difference (.DELTA.V) between both ends of a ringer sending resistor, having a first circuit (S1, S2, A1.about.B3) converting the voltage difference to a current difference, and further having a second circuit (F) converting the current difference to a voltage, the voltage difference varying in response to the on-hook state or the off-hook state of the telephone, and a state detecting circuit (3) for detecting the on-hook state or the off-hook state in response to a value of the voltage from the voltage detecting circuit. The voltage detecting circuit is formed by a plurality of current mirror circuits, each of which includes at least two transistors.
    Type: Grant
    Filed: February 21, 1989
    Date of Patent: February 19, 1991
    Assignee: Fujitsu Limited
    Inventors: Toshiro Tojo, Kenji Takato, Kazumi Kinoshita, Yuzo Yamamoto, Yozo Iketani, Shin-ichi Ito
  • Patent number: 4750200
    Abstract: A call meter signal receiver is provided for a subscriber's private metering system operated by a call meter signal sent from a central office. The receiver is operable both by common mode and normal mode signals. The receiver is small sized and can be installed in a central office trunk of private branch exchanger equipment. The call meter signal receiver is composed of a frequency tuned receiver including two buffer circuits, the first one for receiving the common mode and the second one for receiving the normal mode signal. The first buffer circuit is connected to the input side of a hybrid circuit of the COT, and has a high impedance, while the second buffer circuit, for receiving the normal mode signal, is connected to one of the output terminals of the hybrid circuit, and has a high impedance for voice signals.
    Type: Grant
    Filed: March 20, 1987
    Date of Patent: June 7, 1988
    Assignee: Fujitsu Limited
    Inventors: Kazuhiro Sato, Yoshimi Iijima, Hiroyoshi Mori