Patents
Sitemap › H04 - Electric communication technique › H04M - Telephonic communication › H04M 19 - Current supply arrangements for telephone systems
Patents for H04M 19 - Current supply arrangements for telephone systems (7,475)
08/1981
08/04/1981US4282409 Speech networks for telephone sets
08/04/1981US4282407 Telephone loop resistance detector
07/1981
07/29/1981EP0032590A1 Circuit for recognizing the response of a subscriber in telephone exchanges
07/22/1981EP0032365A1 Supervision device for a digital signal generator
07/21/1981US4280091 Variable current source having a programmable current-steering network
07/21/1981CA1105626A1 Carrier subscriber telephone station terminal loop current booster
07/15/1981EP0031916A1 Electro-optic ringer
06/1981
06/30/1981US4276639 Telephone exchange with time shared speech paths and selectively attenuated speech signals
06/30/1981US4276448 Electronic tone ringer
06/30/1981US4276447 Signal processing apparatus for subscriber circuits
06/30/1981CA1104277A1 Electronic audio signalling device for telephones
06/24/1981EP0030739A1 Circuit for storing the energy of an applied signal for use in a telephone annunciator
06/23/1981US4275277 Subscriber line interface circuit for a telephone line
06/16/1981US4273964 Ring and tone plant
06/10/1981EP0030228A2 Speech networks for telephone sets
06/10/1981EP0030006A1 Circuit arrangement for the remote supply of intermediate posts in a telecommunication contrivance with monitoring of the output voltage of at least one supply unit
06/10/1981EP0030004A1 Circuit arrangement for the remote supply of intermediate posts in a telecommunication contrivance by means of direct current series supply
06/09/1981US4272656 Quasi-resistive battery feed for telephone circuits
06/09/1981US4272650 Power supply system
06/03/1981EP0029823A1 Current weighting circuit
06/03/1981EP0029627A1 Device for detecting the looping of a subscriber line during ringing
05/1981
05/26/1981US4270028 Digitally activated ringing circuit for generation of AC voltages
05/26/1981CA1102025A1 Methods and apparatus for special status indication in telephone systems
05/19/1981US4268723 Circuits and methods for initializing the loop current of a telephone set
05/19/1981US4268718 Housing acoustical amplifier
05/12/1981US4267408 Arrangement for applying a signal to a transmission line
05/06/1981EP0028104A1 Signal control system for a time-division speech network
05/05/1981CA1100651A1 Telephone line circuit
04/1981
04/28/1981US4264786 A.C. Signal current transmission trunk circuit for telephone exchange systems
04/16/1981WO1981001090A1 Telephone loop resistance detector
04/14/1981US4262172 Ring-trip detector
04/08/1981EP0026541A1 Voltage stabiliser suitable for a telephone set
04/08/1981EP0026540A1 Voltage stabiliser suitable for use in a telephone set
04/08/1981EP0026413A1 Circuit arrangement for registering the switching state in a circuit especially constituted by subscriber lines in telephone exchanges
04/08/1981EP0026412A1 Circuit arrangement to avoid the adverse effect of the share of alternating tension during the registration of the switching state in a circuit especially constituted by subscriber lines in telephone exchanges
04/08/1981EP0026411A1 Circuit arrangement for determining the switching state of a subscriber line in telephone exchanges
03/1981
03/17/1981CA1097736A1 Dc to dc converter with regulated input impedance
03/11/1981EP0024942A1 Circuits and processes for initializing the loop current of a telephone set
03/05/1981WO1981000657A1 Electronic tone ringer
03/03/1981US4254305 Current limited subscriber line feed circuit
02/1981
02/17/1981US4251694 Tone-ringing circuits and methods for telephone sets
02/11/1981EP0023714A1 Circuitry for powering a current source device delivering a constant working voltage
02/11/1981EP0023695A1 Surveillance circuitry for an input voltage
02/11/1981EP0023692A1 Circuit arrangement for connecting a transmission device of a modem to a telephone line
02/11/1981EP0023682A1 Parallel regulator circuit for producing a constant output voltage
01/1981
01/28/1981EP0022938A1 Device for increasing the parallel inductance of telephone line transformers
01/21/1981EP0022561A1 Device for powering a subscriber set
01/13/1981US4245294 Power supply providing constant power output
01/07/1981EP0021509A1 Electronic subscriber connector
01/06/1981US4243842 Telephone line circuit
01/06/1981CA1093231A1 Device for generating a visual display in response to a varying magnetic field
12/1980
12/23/1980US4241239 Fluxbucking line transformer with electronic equivalent line terminating impedance
12/16/1980US4239941 Ringing signal generator
12/16/1980US4239935 Ringing generator
12/16/1980CA1091834A1 Electric network for use in a subscriber's loop
12/09/1980US4238644 Supply circuit for a subscriber's line circuit
12/02/1980CA1090929A1 Apparatus working with pulse code modulation or similar digitizing techniques and according to time division multiplexing principles for processing information from a number of telephone channels
12/02/1980CA1090928A1 Dual mode telephone subscriber loop current detector
11/1980
11/25/1980CA1090497A1 Line current detection
11/18/1980US4234763 Feeding bridge with d.c.-compensation for both directions of the feed current
11/18/1980US4234762 Ring trip detector circuit
11/12/1980EP0018859A1 Ringing control device
11/04/1980CA1089133A1 Telephone subscriber line circuit
11/04/1980CA1089132A1 Telephone range extender with gain
11/04/1980CA1089131A1 Method and apparatus for compensating for variations in subscribers line lengths and apparatus
10/1980
10/29/1980EP0017764A1 Subscriber line circuit with ground key activation indication, high ohmic commutable feeding and apparatus for ringing-signal generation
10/29/1980EP0017763A1 Subscriber line circuit with ground key activation indication and insulation fault indication
10/28/1980US4230910 Signalling and channel loop test circuits for station carrier telephone system
10/28/1980CA1088685A1 Telephone subscriber line circuit
10/21/1980US4229665 Programmable power supply system
10/07/1980US4227248 PCM Tone signal generator
10/01/1980EP0016672A1 Call device for an automatic subscriber telephone installation with extensions
09/1980
09/16/1980US4223186 Circuit arrangement for line-supplied subscriber stations having dial devices
09/02/1980US4220826 Ringing generator
08/1980
08/19/1980CA1084185A1 Transformerless two-wire/four-wire hybrid with dc sourcing capability
08/12/1980US4217503 Current limiter
07/1980
07/23/1980EP0013332A1 Chopper circuit
07/22/1980US4214131 Electronic audio signalling device for telephones
07/15/1980US4213016 Arrangement for measuring the line condition of a subscriber's line circuit by means of a measuring resistor
07/15/1980CA1081875A1 Digital measurement of the dc value in an ac signal adapted to telephone off-hook detection
07/09/1980EP0013102A1 Power supply providing constant power output
07/08/1980US4211896 Subscriber's circuit with a symmetrical amplifier
07/01/1980CA1080869A1 Electronic hybrid and hybrid repeater
07/01/1980CA1080866A1 Line conditioning and transfer circuit
06/1980
06/11/1980EP0011720A1 Circuitry for suppressing the influence of interfering voltages at the evaluation of the condition of a signal on transmission lines, particularly on subscriber lines in telephone installations
05/1980
05/27/1980US4205204 Telephone loop extending apparatus
05/20/1980CA1078048A1 Method of and arrangement for switching a service information
05/14/1980EP0010720A1 Fully electronic loop closure circuit
05/13/1980US4203012 Hybrid circuit using current mirror circuits
05/13/1980US4203009 Unbalanced/balanced converter circuits
05/06/1980US4201897 Ringing voltage transfer circuit
04/1980
04/29/1980US4200435 Determination of glycosylated hemoglobin in blood
04/22/1980US4199664 Telephone line circuit
04/22/1980CA1076278A1 Peak shut-off electronic switch
04/15/1980CA1075840A1 Circuit for interfacing an audio frequency line to a central unit
04/15/1980CA1075778A1 Hybrid circuit
04/08/1980US4197432 Telephone subscriber's loop power control circuit
04/08/1980US4197431 Subscriber loop feed apparatus
04/08/1980US4197425 Power supply circuit for a subscriber's telephone set
04/02/1980EP0009127A1 Circuit for a line-fed loudspeaking telephone station
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