Matches 201 - 250 out of 260 < 1 2 3 4 5 6 >
Match Document Document Title
4251693 Fixed impulse generator for hook switch flash  
A hook switch flash generator to provide consistent, electronically controlled and timed flash signals independent of human variables. A user operated button switch is closed to initiate...
4239935 Ringing generator  
A ringing signal generator is disclosed for remotely generating telephone ringing signals having a trapezoidal waveform. A single capacitor and two constant current sources control the wave shape...
4220826 Ringing generator  
A ringing signal supply for supplying ringing current to a telephone line with high efficiency and minimum distortion. As the ringing current demand of a load increases, distortion of the output...
4219699 Telephone supervision system using DTMF signals  
A station-to-station supervision system for a telephone system has a dual tone multiple frequency (DTMF) signal generator connected to the transmit line at each subscriber station, and a standard...
4192007 Programmable ringing generator  
An apparatus for generating a selected one of a plurality of ringing frequencies utilizing a single frequency source. A first counting means is utilized to divide the source frequency by a first...
4171466 Digital wave generator for composite tone  
Digital words defining magnitude levels of samples of phases of a wave cycle are stored in two memories arranged to store samples of 440 Hz and 480 Hz tones. The words are read out of the memories...
4156150 Circuit for regulating a DC voltage on which a large AC voltage is superimposed  
Disclosed is a ringing power supply for developing a ringing signal having an AC voltage combined with a regulated DC voltage, of magnitude smaller than the magnitude of the AC voltage, from a...
4152546 Ringer power generator circuit for carrier subscriber station terminal  
A ringer-power generator circuit is provided in which ring pulses cause positive and negative output voltages of a swinging choke regulator to be alternately connected to one of the tip and ring...
4140882 Methods and apparatus for special status indication in telephone systems  
A telephone system usable for example in hotels or the like and in which each of a plurality of telephone sets is equipped with a special status indicator or signal light as well as the usual bell,...
4139740 Flash-wink generating circuit  
A circuit for detecting ringing signals on a telephone line in which the alternating voltage oscillations are converted to direct current pulses which are used to charge a first capacitor. Only...
4081617 Electronic ringing circuit for telephone systems  
This invention relates to an electronic ringing circuit for telephone systems. The inventive circuit provides a dual tone output with the tones changing at a predetermined rate. The circuit...
4064367 Dual tone selector with answerback signalling  
A function control code sequence of signals, each comprising a pair of audio frequency tones, is transmitted from a control location to a remote station selector. Each input signal is applied to a...
4056693 Voltage and current controlled converter for telephone ringing  
A single channel carrier system for telephone service is disclosed including a remote terminal having a ringing generator included therein for generating ringing signals to operate the ringers of...
4025729 Telephone ringing control circuits  
A single channel carrier system is disclosed including a remote terminal having a battery charger for charging a battery during idle periods to power the remote carrier electronics. The remote...
4015091 Telephone ringing generators  
A single channel carrier system for telephone service is disclosed including a remote terminal having a battery charger for charging a battery during idle periods to power the remote carrier...
4012702 Chime generating circuit  
A circuit for electronically generating chime-like tones wherein an oscillator circuit output is passed through a diode bridge having another diode across the D.C. terminals thereof and poled to be...
3946164 Precise tone signal generator  
A circuit for generating precise tone signals for use in telecommunications systems, such as dial tone, busy tone, ringback tone, etc. the circuit provides tone signals at a level suitable for...
3941941 Relayless switching circuit for application of ringing signals  
A relayless switching circuit which provides an effectively open circuit between a telephone and a ringing generator when the ringing generator is de-energized and which is conditioned when the...
3927266 Ringer power generator circuit for subscriber carrier station terminal  
In a subscriber carrier station terminal including a two-wire drop that is associated with a VF hybrid circuit and a handset thereof, a DC ringer voltage is generated by a DC-DC converter that is...
3919492 Solid state interrupter  
An interrupter for use in telephone signalling systems or the like is comprised entirely of solid state circuitry to perform switching functions to provide from a plurality of AC and DC input...
3909535 Telephone coupler unit  
A telephone coupler unit is provided which can be coupled to the telephone lines associated with a local telephone instrument. The circuits of the telephone coupler unit include filter means that...
3904833 Ringing generator circuit with capacitor storage  
A ringing generator circuit in which a capacitor is charged by the central office d.c. power source and in which the charge stored by the capacitor is applied, in response to a ring control signal,...
3809813 TELEPHONE ALARM SIGNALLING SYSTEM  
A system for indicating an abnormal condition at premises provided with a telephone subscriber station having a telephone callable from an outside station. The system includes a series connection...
3764752 TELEPHONE LINE CARD SYSTEM  
A telephone line card circuit including electrical devices and circuitry for minimizing the electrical components by providing an optical detector for controlling the input to an integrated circuit...
3731004 IMPEDANCE MATCHING CIRCUIT FOR TONE RINGING  
The invention relates to an impedance matching circuit designed to minimize current drain on the supply thereto while maintaining maximum current driving efficiency through a load and particularly...
3730999 TELEPHONE RING-TRIP CIRCUIT  
A discharge circuit prevents charge buildup on the plates of a capacitor in a telephone ring-trip circuit over each A.C. cycle of ringing current until a telephone call is answered, thereby...
3710032 TELEPHONE SILENCING APPARATUS AND METHOD  
Method and apparatus for selectively silencing the bell of a telephone wherein the method comprises selectively reducing the resultant magnetomotive force through the ringer circuit to a value...
3581020 RINGING TONE DISTRIBUTION CIRCUITS  
A logic system is provided for supplying ringing tone in successive bursts of one-second duration to each of four bays. The system provides the tone in a repetitive cycle so that the load of only...
3536852 TELEPHONE INTERRUPTION SWITCHING CIRCUITRY  
3502812 VIDEOTELEPHONE SYSTEM FOR PROVIDING A VISUAL DISPLAY OF CALL PROGRESS SIGNALS  
3433902 SPEECH IMMUNITY VOICE FREQUENCY SIGNALLING SYSTEMS  
3428755 HYBRID TERMINATION SWITCH RESPONSIVE TO RINGING SIGNAL  
3349185 Ringing curent converting circuit  
3341665 Interrupter circuit for telephone systems  
3313886 V-f key-dialling  
3300589 Telephone ringing circuits  
3248634 Electronic ringing generator  
3223787 Telephone ringing control system  
3187108 Subscribers' telephone equipment  
3164680 Signalling system for substation apparatus  
3145266 A. c. static switching circuits  
3076059 Signaling system  
3064081 Communication call apparatus  
3064085 Absence sign device for telephone  
3059061 Telephone signaling frequencies generator  
3033941 Means for altering telephone operation  
2990454 Telephone systems  
2980863 Ringing tone generator  
2938082 Telephone apparatus  
2914624 Automatic routiner for selector and connector switches  
Matches 201 - 250 out of 260 < 1 2 3 4 5 6 >