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)
04/1980
04/02/1980EP0009106A1 Circuit arrangement for energizing an electromagnet in a coin-freed telephone station
04/01/1980CA1074935A1 Subscriber equipment for telephone exchange
03/1980
03/25/1980CA1074425A1 Decoupling control arrangement for auxiliary circuits coupled to telephone lines
03/18/1980US4194151 Multifrequency generator
03/18/1980US4194091 Line feed circuit
03/18/1980CA1074034A1 Telephone line circuit with differential loop current sensing and compensation
03/18/1980CA1074033A1 Resistive battery feed for line circuits
03/11/1980US4192975 Supply-arrangement for a line circuit
03/11/1980CA1073569A1 Method of monitoring the on/off-hook status of a telephone set connected to a telephone network
03/04/1980US4192007 Programmable ringing generator
03/04/1980US4191859 Loop, dial pulse and ring trip detection circuit with capacitive shunt network
02/1980
02/19/1980US4189764 Current controlled inverter
02/19/1980US4189626 Electronic tone ringer for telephone sets
02/06/1980EP0007628A1 Circuit for the remote feeding of intermediate stations in a telecommunication arrangement
02/06/1980EP0007626A1 Circuit for remotely powering intermediary stations in an arrangement related to the information transmission technology
01/1980
01/15/1980CA1069974A1 Digitally regulated inverter
01/09/1980EP0006583A1 Method for supplying a call and line current without inductances, relay contacts or transformers
01/08/1980US4182936 Transformerless trunk circuit
01/08/1980CA1069633A1 Balanced tone application system
01/08/1980CA1069632A1 Telephone line battery boost circuit
01/01/1980CA1069232A Loop extender
12/1979
12/11/1979US4178485 Transformerless telephone line circuit
11/1979
11/27/1979US4176255 Adjustable impedance battery feed circuit
11/20/1979US4175218 Telephone switching system
11/13/1979US4174467 Ringing signal generator for use in a subscriber's line circuit
10/1979
10/31/1979EP0004901A2 Circuit for subscriber stations with selecting means and current supply over the lines in telecommunication systems, especially telephone systems
10/02/1979CA1063743A1 Telephone line loop-detecting circuits
10/02/1979CA1063742A1 Telephone ringing control circuits
10/02/1979CA1063741A1 Telephone ringing generators for subscriber loop carrier telephone systems
09/1979
09/25/1979CA1063271A1 Signal sending control system
09/18/1979CA1062823A1 Electronic current feed circuit
09/11/1979US4167654 Telephone line feeding circuit including a protective device
09/04/1979US4166930 Transient free ring relay circuit for arbitrary time switching
09/04/1979US4166928 Loop, dial pulse and ring trip detection circuit
08/1979
08/28/1979US4165949 High efficiency split flow turbine for compressible fluids
08/14/1979US4164713 Dual mode telephone subscriber loop current detector
08/07/1979US4163873 Telephone solid state ringer
07/1979
07/31/1979CA1059667A1 Telephone ringer isolator
06/1979
06/26/1979CA1057437A1 Subscriber's circuit for four-wire-system local switch
06/19/1979US4158752 Carrier subscriber telephone station terminal loop current booster
06/12/1979US4158170 Line current detector
06/05/1979US4157459 Electronic audio signalling device for telephones
05/1979
05/22/1979US4156150 Circuit for regulating a DC voltage on which a large AC voltage is superimposed
05/15/1979US4154989 Call-signal receiver for station of telecommunication system
05/01/1979US4152670 Signal generator, especially for ringing current in telecommunication system
04/1979
04/18/1979EP0001522A1 Electronic line equipment with two-wire-four-wire conversion circuit for telephone exchange
04/17/1979US4150260 Subscriber's circuit for four-wire-system local switch
04/05/1979WO1979000158A1 Electronic equipment for users,with two wires-four wires conversion circuit for a telephone switch center
03/1979
03/27/1979US4146754 Telephone signalling method and apparatus
03/27/1979CA1051569A1 Crescendo control of signalling devices
03/20/1979US4145577 Ringing control apparatus
03/20/1979US4145572 Power supply control circuit for subscriber carrier telephone system
03/13/1979US4144408 Telephone ringing extender
03/07/1979EP0000990A1 Unbalanced/balanced converter circuits
02/1979
02/27/1979US4142075 Interface circuit and method for telephone extension lines
02/20/1979US4140884 Electronic tone ringer
02/20/1979US4140882 Methods and apparatus for special status indication in telephone systems
02/13/1979US4139740 Flash-wink generating circuit
01/1979
01/16/1979US4135062 Electric network for use in a subscriber's loop
01/09/1979US4133986 Subscriber's line equipment for a telephone exchange
01/02/1979US4132864 Digital measurement of the DC value in an AC signal adapted to telephone off-hook detection
12/1978
12/26/1978US4131770 Common bell ringing apparatus for multiple button key telephone set
12/26/1978CA1045215A1 Automatic disconnect circuit for subscriber carrier telephone system
12/19/1978US4130735 Loop extender
11/1978
11/28/1978US4127747 Voltage boost circuit for telephone systems
11/07/1978US4124884 DC to DC converter with regulated input impedance
11/07/1978CA1042122A1 Current supply system for subscriber line circuits
10/1978
10/24/1978US4122312 Loop extender
09/1978
09/26/1978CA1039423A2 Lamp power supply arrangement for key telephone system
09/19/1978US4115660 Telephone line interfacing circuit with directional transfer of ringing current and off-hook indications
09/19/1978CA1038981A1 Interrupter for key telephone systems
09/12/1978US4113990 Signal sending control system
08/1978
08/29/1978US4110636 Feeding bridge
08/29/1978US4110569 Method and apparatus for monitoring the on/off-hook status of a telephone set
08/15/1978US4107495 Electronic tone ringer
08/15/1978US4107476 Electronic tone ringer control circuit for a telephone set
08/15/1978CA1036736A1 Self-adjusting voice frequency repeater
08/01/1978US4104488 Subscriber line circuit
08/01/1978CA1035837A1 Direct current regulating device
07/1978
07/25/1978US4103112 Telephone line circuit with differential loop current sensing and compensation
07/18/1978US4101871 Touch-tone encoder unit for mobile radio transmitter
07/04/1978US4099032 Loop current detector
06/1978
06/20/1978US4096363 Transmission network including flux compensation
05/1978
05/30/1978US4092489 Switching arrangement for monitoring polarity reversal on lines in telecommunication systems
05/09/1978US4088843 Electronic current feed circuit
05/02/1978US4087647 Circuit for supplying direct current to telephone station sets
05/02/1978US4087646 Dual mode telephone subscriber loop current detector
04/1978
04/25/1978US4086447 Electronic hybrid circuit for connecting a two-wire line to switching system
04/25/1978US4086440 Telephone set with loop current interruption timing control
03/1978
03/28/1978US4081619 Switching arrangement for telecommunication subscriber stations using key-operated selection units
03/28/1978US4081617 Electronic ringing circuit for telephone systems
03/28/1978US4081609 Synchronous ring detector for station carrier telephone systems
03/28/1978US4081130 Filter-type pulse detection means
03/14/1978US4079208 Telecommunications transmission and signalling circuits
02/1978
02/28/1978US4076968 Telephone ringer intensity control responsive to ambient noise
01/1978
01/31/1978US4071709 Line conditioning and transfer circuit
01/17/1978US4069396 Power saving circuit for use with a converter circuit in a telephone switching installation
01/10/1978US4068099 Method of and apparatus for switching service information units in a TDM system
12/1977
12/27/1977US4065755 Touch-Tone encoder unit for mobile radio transmitter
12/20/1977US4064449 Direct current compensation circuit for transformers
1 ... 64 65 66 67 68 69 70 71 72 73 74 75