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Match Document Document Title
7224793 Communication set with detection of set function and line condition  
A description is given of a communication set for connection to a communication line such as a telephone line, which communication set includes means for detecting set functions such as ringing...
7206403 Telephone terminal equipment interface circuit  
The object of the present invention is to remove the dead region of a diode bridge and maintain stable operations in a telephone terminal equipment interface circuit. In order to realize this...
7103175 Systems and methods for an electronic hook switch for customer premises equipment  
Embodiments of the present invention relate to systems and methods for an electronic hook switch for customer premises equipment. In an embodiment, a system includes a first lead configured to be...
7094110 Computer disconnect device  
A computer disconnect device that may have an external communications cable connector; a jumper communications cable connector; a switch; external wiring for connecting the external communications...
6925170 Wire-bound telecommunication device and a circuit for use in such a device  
In known telephone subscriber end stations a caller_ID IC detects a tone alerting signal TAS alerting that successive caller_ID information can be received for displaying on a display of the phone....
6868156 Non-voice signal repeater for speech coders  
A method of repeating a non-voice signal such as a dual tone, multiple frequency (DTMF) signal, by inserting a delay sequence of data values into an output data sequence of data values, a portion...
6845157 Linear polarity guard and method for DSL-ready pots devices  
A plain old telephone system (POTS) device, for example but not limited to, a telephone, facsimile machine, analog modem, caller identification (ID) system, speaker phone, cordless phone, etc.,...
6829352 Amplifier arrangement  
Amplifier arrangement comprising: a resistive receive hybrid means adapted to pass a combination of a received signal and a transmitted signal, a resistive transmit hybrid means adapted to pass...
6631190 Telephone system  
A telephone system capable of judging kinds of various signals (line input signals) obtained through a line is disclosed, that enables reduction of the number of parts, detection with high...
6393123 Method and modem circuit for determining connection status of a phone line  
A circuit for determining connection status of a phone line shared by multiple telecommunications devices, such as modems and phones, is provided. The phone line includes respective tip and ring...
6141416 Analog telephone subscriber terminal apparatus  
An analog telephone subscriber terminal apparatus with means for realizing additional functions is provided. In the on-hook state of the subscriber terminal apparatus, and outside of the idle...
6044150 Method and apparatus for a host-based personal computer speakerphone  
A method and apparatus for implementing a speakerphone within a personal computer having a voice-capable modem and an audio board is provided. The personal computer executes host software providing...
5812658 Method and circuit for failsafe switch-hook detection during fault in a telephone system  
A circuit and method for maintaining switch-hook detection (SHD) in the presence of a fault in a telephone system may include a comparison of one of a tip current and a ring current to a reference...
5659602 Telephone apparatus for caller ID  
A telephone apparatus for connection to central office equipment to receive a caller ID signal therefrom and having an operating mode in which line current is less than a threshold at which...
5600715 Integrated loop current detector apparatus for a PSTN modem  
An integrated loop current detector for a public switched telephone network modem. The present invention solves the loop current detect problem in general, and is especially useful in modems...
5559873 Telephone privacy device with conference and indicator features  
A simple and inexpensive telephone exclusion or privacy device. A conference feature is and am indicator light showing when the line is in use are also provided. The basic exclusion or privacy...
5461670 Telephone subscriber system incorporating a drive interface for a telephone line switch at a different reference potential  
A telephone subscriber system comprising a speech circuit and a ring circuit adapted to be integrated monolithically to a semiconductor material substrate and being coupled to a telephone...
5287404 Telephone subscriber line voltage change detection  
Changes in a telephone subscriber line voltage are detected in a telephone set by supplying a voltage dependent upon the subscriber line voltage to a potential divider having first, second, and...
5255182 Payment card point-of-sale service quality monitoring system, apparatus, and method  
A system for determining the cause of lost, delayed or erroneous responses in a network for authorizing payment card transactions from the point of view of the point-of-sale terminal that forms...
5155764 Telephone set with on-hook line seizure  
A telephone set is provided enabling seizure for originating and terminating calls of a telephone line connected thereto to be performed as well as release thereof, as the result both of a first...
5111502 Telephone line bridging sensor  
A telephone line bridging sensor circuit is provided which provides a variable output frequency signal to a microprocessor for measuring and storing the frequency count on a periodic basis. The...
5020100 Telephone line loop current regulator  
A telephone line loop current regulator combines the functions of current regulation, current detection, loop disconnect signalling and speech switching. It comprises a gyrator circuit formed by...
4935959 Two-wire telecommunications line detection arrangements  
A loop closure detector for a two-wire telephone line comprises a four-arm resistive bridge, in which the four arms are constituted respectively by a first battery feed resistor, the two-wire line...
4899379 Circuit arrangement for the connection of line circuits of a digital time multiplex-telephone network  
A circuit for implementing a connection of an operational amplifier, and for achieving the switchable sensitivity of the same, as well as the in-and-out switchable filter elements, which results in...
4864605 Telephone trunk interface circuit  
A solid-state telephone trunk interface circuit provides high isolation between a central office and telephone equipment. Opto-isolator transistors and a transformer are used to isolate the central...
4841568 Circuit arrangement for a telephone station with earth connection to the central supply device  
A circuit arrangement for a telephone station with earth connection to the central supply device for the purpose of post-dialing signaling, operates independently of whether the negative or the...
4809322 Circuit arrangement for a telephone station with ground connection  
The invention relates to a circuit arrangement for a telephone station with ground connection to a central supply device for the purpose of post-dialling signalling. The circuit arrangement...
4454477 Loop current detector with threshold setting impedance  
In a loop circuit closure detector, a circuit which connects a voltage comparator to the loop circuit is biased so that the comparator indicates loop circuit closure at a predetermined minimum...
4444999 Automatic electronic disconnector for subscriber terminal equipment  
An electronic circuit means for automatically disconnecting an off-hook subscriber's first telephonic signal sending and receiving terminal device which is in an off-hook mode when a second...
4439634 Carrier subscriber telephone off-hook detector  
A resistor and diode means are electrically connected in series between nodes A and B on the base electrodes of first and second transistors of a differential amplifier. These nodes A & B are also...
4320265 Line repeater for telephone system using radio links  
A telephone exchange communicates with a number of scattered local stations via radio links extending from a central terminal to respective peripheral installations each comprising a radio...
4319092 Current detection circuit arrangement for an automatic telephone exchange  
Current detection circuit arrangement for an automatic telephone exchange for detecting currents in a system of two conductors having earth as the common return conductor. This circuit arrangement...
4224478 Data transmission circuit for establishing a bidirectional data path in a telephone system  
A data transmission circuit for use in a telephone system. The telephone system includes a telephone line connected with tip and ring terminals and a subscriber telephone coupled across the tip and...
4220825 Telephone status monitor circit  
A telephone status monitor circuit for determining the on/hook and off/hook conditions of a telephone connected across standard tip and ring terminals of a telephone system. The telephone status...
4216355 Telephone line monitoring apparatus  
An apparatus is disclosed for monitoring the busy or free condition of telephone subscribers' lines, comprising a number of bridge circuits, each connected to one of the subscribers' lines. Each...
4172215 Transformer coupling circuit providing for cancellation of D.C. fluxes  
In a coupling circuit for A.C. coupling a switching network to a trunk circuit through a coupling transformer, a magnetic flux cancel circuit is provided for canceling non-varying magnetic fluxes...
4151377 High impedance loop-seizing and dial pulsing circuit  
An improved loop-seizing and dial pulsing circuit arrangement of the type employed in telephone trunks has an extremely low insertion loss. The circuit comprises a diode bridge connected across a...
4126765 Detector circuit for sensing battery polarity and loop closure  
A detector circuit for use in conjunction with a trunk circuit of a PABX telephone system interfacing with a central office providing for constant monitoring of normal or reverse battery...
4105872 Electronic telephone system including interexchange trunk repeaters for traffic with other systems  
An electronic telephone switching system is described having peripheral units including a plurality of subscriber and line circuits, a plurality of trunk and tie line circuits, at least one...
4099032 Loop current detector  
A ground start loop current detector is used to monitor the loop current in a telephone subscriber loop when the subscriber requests service by grounding one line of the loop (ground start), when a...
4087646 Dual mode telephone subscriber loop current detector  
A detector circuit is shown for detecting off-hook and dial pulse signals in a telephone system which, under the control of a ringing relay, reconfigures itself to provide ring-trip detection. The...
4049919 Communication system trunk circuit  
A trunk circuit for interconnecting an electronic and a step-by-step electromechanical switching exchange including a sensing circuit that is transparent to the transmission and supervisory...
3974343 Small modular communications switching system with distributed programmable control  
A telephone central office switching system with economical application to small community dial office sizes is disclosed. Communication paths are spatially switched over a modular network fabric...
3894192 DX signaling circuit  
An electronic DX signaling circuit for detection of DC signals on a two-way telephone trunk circuit. A bridge network connects to a cable pair, and a voltage detection circuit connects to four...
3748395 D.C. MONITOR CIRCUIT  
A resistor network is connected to a two wire line and used to detect and overcome changes of direct current levels without disturbing any alternating current signals superimposed thereon. Direct...
3731012 CURRENT LIMITING AND RESISTANCE MONITORING CIRCUIT  
A current limiting and resistance monitoring circuit provides a means for limiting the amount of current flow to a telephone connection connected thereto and for generating a control signal having...
3622709 SUPERVISORY CIRCUIT FOR TELEPHONE LINES  
A supervisory detection circuit of monitoring the operative state of communication lines in a telephone system in whidh a pair of voltage dividers are cross-connected across the battery feed...
3546392 COORDINATE MATRIX ARRANGEMENT FOR SUPERVISION OF LOOP CONDITIONS AND FOR DISCERNING LOOP RESISTANCES IN A PLURALITY OF LOOPS  
3525816 LOOP SUPERVISION CIRCUITRY  
A resistor network is connected to a two wire line and used to detect and overcome changes of direct current levels without disturbing any alternating current signals superimposed thereon. Direct...
3515809 SUPERVISORY CIRCUIT ARRANGEMENTS  
Matches 1 - 50 out of 57 1 2 >