Patents for H04M 19 - Current supply arrangements for telephone systems (7,475) |
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04/27/1994 | EP0593556A1 Telephone marketing system |
04/26/1994 | US5307407 20 Hz ring generator using high frequency PWM control |
04/26/1994 | US5307406 ISDN power source detection circuit |
04/20/1994 | EP0592493A1 Personal communication system providing supplemental information mode |
04/19/1994 | US5304917 Compact low noise low power dual mode battery charging circuit |
04/19/1994 | CA2006554C Electrical apparatus power switch and remote control terminal apparatus equipped with said switch |
04/12/1994 | US5303284 Ringing circuit for use in portable telephone set |
04/06/1994 | EP0590242A1 Circuit arrangement to feed digital terminals with simulated-inductance circuits |
04/05/1994 | CA2004690C Current limit circuit for ringing amplifier |
03/24/1994 | DE4231389A1 Variable control current supply circuit contg. two current paths - produces subsidiary control signal for variation of current in one path to steepen slopes of output current waveform. |
03/24/1994 | DE4222401A1 Telephone call signal processing arrangement - uses call tone recognition circuit which either accepts or rejects a clock signal depending on position in signal band. |
03/23/1994 | EP0587966A1 Circuit arrangment for priority-feeding of devices from the loop current |
03/23/1994 | EP0587575A1 Telephone line interface circuit with voltage switching |
03/17/1994 | WO1994006254A1 Cordless telephone system with different ringing patterns |
03/17/1994 | WO1994006215A1 Communication device connected to an interface circuit employing opto-isolators |
03/16/1994 | EP0586906A2 Mobile communications equipment |
03/15/1994 | US5295185 Ringing signal generation circuit with protection against overvoltage |
03/15/1994 | CA2025140C Communication terminal having means for controlling power transfer |
03/15/1994 | CA2001472C Data circuit-terminating equipment with power source device attached thereto |
03/10/1994 | DE4241306C1 Telephone subscriber circuit with back-up voltage supply - uses capacitor charged automatically from exchange line under control of normal telephone function |
03/08/1994 | US5293420 Ring trip circuit |
03/08/1994 | CA2005260C Telephone ringing detector |
03/02/1994 | CN1083296A Low power emergency telephone mode |
02/28/1994 | CA2077052A1 Incoming call manager |
02/22/1994 | US5289537 On-hook transmission circuit in cable line |
02/22/1994 | US5289359 DC-DC power converter including sensing means for providing an output when the reserve power of the converter falls below a predetermined amount for a given input voltage |
02/17/1994 | WO1994003990A1 Isolation interface apparatus |
02/17/1994 | DE4237395C1 Verfahren zum Programmieren einer Basisstation mit Hilfe eines Mobilteils A method for programming a base station with the aid of a handset |
02/16/1994 | EP0233892B1 A telephone line switch |
02/09/1994 | EP0582439A1 Subscriber line interface circuit with impedance synthesis |
02/09/1994 | CN1081798A A communications device |
02/07/1994 | CA2097354A1 Battery feed circuit |
01/26/1994 | EP0580340A1 Telephone apparatus and method |
01/26/1994 | EP0580249A2 Method and device for the matching of the impedances of the subscriber termination and of the subscriber access to the characteristic impedance of the subscriber telephone line |
01/20/1994 | DE4222977A1 Telephone subscriber unit with telephone terminal - allows subscriber to program and store individual acoustic signals such as music or speech to be played back when triggered. |
01/19/1994 | EP0579557A1 Portable facsimile apparatus |
01/18/1994 | US5280523 Telephone line message waiting and ring indicator |
01/13/1994 | DE4236811C1 Verfahren zum Laden von Akkumulatoren in schnurlosen Kommunikationsendeinrichtungen und Anordnung zur Durchführung des Verfahrens Method for charging batteries in cordless communication terminal equipment and arrangement for carrying out the method |
01/05/1994 | EP0577474A1 Ringing circuit for telephone set |
01/05/1994 | EP0577057A2 Line termination of a telephone line |
12/29/1993 | EP0576209A1 Remote charging cradle for cordless telephone handset |
12/28/1993 | US5274704 Transformer telephone line interface circuit |
12/28/1993 | US5274703 Automatic loss control circuit |
12/28/1993 | US5274702 For a two-wire telecommunications line |
12/28/1993 | US5274701 Telephone alerter |
12/16/1993 | DE4218845A1 Ringing tone voltage generator including PWM - is entirely integrated except for transformer whose sec. winding feeds amplitude-regulating operational amplifier and discharge transistor |
12/14/1993 | US5271059 Method and configuration for forming a line termination of a telephone line |
12/09/1993 | WO1993025037A1 Low loss telephone circuit |
12/08/1993 | EP0572872A2 Circuit arrangement for reducing power consumption of a telecommunication terminal |
12/08/1993 | CN1023051C Communication central exchange |
12/02/1993 | DE4217297A1 Wide band communication system optical network current supply - supplies electric energy for opto-electric conversion and to devices at subscriber end individually from subscriber |
11/24/1993 | EP0570425A1 An emergency call unit |
11/18/1993 | EP0569582A1 Telephone ringing signal generator |
11/09/1993 | US5260996 Current limited electronic ringing generator |
11/09/1993 | US5260995 Electric power circuit for telephone set use |
11/09/1993 | US5260992 Key telephone system with reduction of delay of ring tone generation at telephone set |
11/09/1993 | US5260937 Power conserving technique for a communications terminal time slot interchanger |
11/03/1993 | CN1078080A Hybrid fiber in the loop telephony system |
11/02/1993 | US5258713 Impedance generator for a telephone line interface circuit |
11/02/1993 | CA2020870C Radio telecommunication apparatus |
10/28/1993 | WO1993021724A1 Subscriber line interface circuit with voltage controlled loop current |
10/28/1993 | WO1993021723A1 Impedance synthesizer for a subscriber line interface circuit |
10/28/1993 | WO1993021722A1 Wideband telephone line interface circuit |
10/21/1993 | DE4214125C1 Signal level and frequency monitoring for telephone call tone circuit - feeding frequency information for call tone input signal to microprocessor via DC voltage converter providing galvanic separation |
10/20/1993 | EP0565859A1 Telephone ringer circuit |
10/19/1993 | US5255317 ISND (Integrated Services Digital Network) and POTS (Plain Old Telephone |
10/14/1993 | WO1993020646A1 Combined supply voltage connection and call a.c. voltage generator and connection for analog telephone receiver stations in extension installations |
10/13/1993 | EP0402360B1 Impedance synthesis multiple loop using filtering means |
10/13/1993 | CN2143851Y DC power supply equipment for shared wave filter |
10/13/1993 | CN1077321A Radio selective call receiver |
10/12/1993 | US5253290 Circuit arrangement for the transmission of telecommunication signals |
10/12/1993 | US5253289 In accordance with ringing signal sequences sent through telephone line |
10/07/1993 | DE4211819A1 Hands-free telephone circuit with dynamic loudspeaker - provides loudspeaking and call tone output stages connected in parallel to loudspeaker for providing call tone signal |
10/06/1993 | EP0564127A2 Chameleon apparatus housing unit |
10/04/1993 | WO1993020645A1 Telephone line interface circuit with voltage switching |
09/28/1993 | US5249226 Apparatus for controlling a current supply device |
09/23/1993 | DE4231938C1 Electronic circuit supplying calling signal to subscriber lines - interrupts calling order repeatedly for short intervals at zero-crossings for transitory re-imposition of supply voltage |
09/21/1993 | US5247573 Telecommunications system comprising a circuit arrangement for at least one subscriber station |
09/16/1993 | WO1993018609A1 Circuitry for superimposing small, low energy signals and large, essentially higher energy signals |
09/16/1993 | WO1993018605A1 Hybrid fiber in the loop telephony system |
09/16/1993 | DE4226423C1 Ringing signal display circuit for 2-wire telephone line - uses angularly offset sensor wires around outside of telephone line with evaluation of obtd. signal differences |
09/16/1993 | CA2117555A1 Hybrid fiber in the loop telephony system |
09/15/1993 | EP0560236A2 Method and switching-arrangement for transmission of digital signals on subscriber-lines |
09/15/1993 | CN2142247Y Combination power supply using for communication network of countryside |
09/09/1993 | DE4206762A1 Ringing-tone generator circuit for telephone subscriber's appts. - employs integrated circuit with fewer pins to detect zero-crossings of incoming signal and switch electro acoustic ringer |
09/08/1993 | EP0559336A2 Apparatus for controlling a current supply device |
09/02/1993 | WO1993017514A1 Telephone subscriber line circuit, components and methods |
09/02/1993 | CA2130183A1 Telephone subscriber line circuit, components and methods |
08/25/1993 | EP0556742A1 Acoustic feedback suppression device particularly for auxiliary ringers in plug-in telephone systems |
08/24/1993 | US5239580 Modem-telephone coupler |
08/17/1993 | US5237606 Enhanced synchronous rectifier |
08/12/1993 | DE4203477A1 Emergency operation circuitry for communication terminal devices - forms direct connection between mains and device with digital line when device current supply fails |
08/10/1993 | CA1321239C Animated data display interleaving |
08/05/1993 | DE4202874A1 Quiescent current supply circuit for telecommunication terminal - is either installed as auxiliary equipment or integrated into receiving appts. which is switched on when incoming message is recognised |
08/04/1993 | EP0554196A1 Telephone line current modulator |
08/04/1993 | EP0554192A1 Power regulator for the loudspeaker of a telephone unit |
08/03/1993 | US5233649 Telephone ringing module |
08/03/1993 | US5233641 Radio telephone equipment having a sounding device for generating alert tone indicative of response of called subscriber |
08/03/1993 | US5233349 Signal transmission system |
07/23/1993 | WO1993015590A1 Radio with silent and audible alerts |