Abstract: The present application relates to the field of circuit design, and discloses a DC-DC conversion circuit system and a forming method thereof. The system may include a primary switch circuit, a charge/discharge circuit, and a secondary switch circuit. The primary switch circuit includes a voltage supply end configured to receive a first direct current voltage and an output end. The charge/discharge circuit includes an input end connected to the output end of the primary switch circuit, and a first output end configured to output a second direct current voltage. The secondary switch circuit includes a voltage supply end configured to receive the first direct current voltage, and an output end connected to the output end of the primary switch circuit. The primary switch circuit is configured to control the charge/discharge circuit to charge or discharge.

Abstract: A system and method of responding to an incoming voice call are described. The method may comprise receiving the incoming call at a voice communication device, monitoring a user input via the voice communication device and generating a user control signal in response to the user input. The user control signal may identify that termination of ring functionality associated with the incoming call is at least to be delayed. Further, a system and method are described of processing a voice call to a voice communication device. The method may comprise communicating the voice call to a voice communication device and receiving from the voice communication device a user control signal in response to a user input. Termination of ring functionality may be at least delayed in response to the user control signal. The invention extends to a device to process a voice call to a voice communication device.

Abstract: Systems for providing a tune master caller identification (ID) device include a telecommunications network and a caller device configured to provide caller identification information for an incoming telephone call, and a tune master caller ID device that is coupled to a telephone device. The tune master caller ID device receives caller identification information, associates a tune with the caller identification information, and plays the tune associated with the caller identification. The telephone device coupled to the tune master caller ID device provides telephone call processing capabilities. Other systems and methods are also provided.

Abstract: A subscriber loop interface circuit and method for externally programming the on-hook, off-hook, and transition states of the subscriber loop interface circuit. The circuit having an off-hook overhead sufficient for long loop applications and having a continuous loop current to loop voltage relationship. The circuit may have plural means for generating reference currents for comparison with loop currents.

Abstract: A multiple bank memory device is described which can be tested by accessing the multiple memory banks simultaneously. The memory includes a test mode trigger which initiates a test which writes and reads from memory cells located in different memory banks. Error detection circuitry evaluates data read from different memory banks and determines if a defect is present in the memory cells. Different test patterns and techniques are described for identifying defective memories.

Abstract: A ring generator circuit is included in a subscriber line interface circuit (SLIC) for providing a high voltage ring signal to a plurality of ringers at the same time. The ring generator circuit includes an adder and divider circuit connected to receive a DC offset and an AC reference signal from the SLIC. The adder and divider circuit outputs a fractionalized summed signal. That signal is supplied to a full-wave rectifier, which rectifies the fractionalized summed signal so that it is always a positive voltage. The rectified signal is supplied to a switch control circuit, a first amplifier and a second amplifier. The first and second amplifiers have the same gain, but with opposite signs or polarities. The outputs of the first and second amplifiers are sent to a commutating switch, which is controlled by an output of the switch control circuit.

Abstract: A telephone switching system is comprised of a main controller, switching circuits controlled by the main controller, a peripheral controller for controlling the seizing of subscriber lines for calls routed through the switching circuits, and further comprising a first memory associated with and accessible by the main controller for storing user data associated with each directory number, the user data comprising a ring type, a second memory associated with the peripheral controller for storing ringing cadence indicators associated with respective plural ring types, the main controller for reading the station data from the first memory upon receiving a request for service to a directory number, and sending the ring type indicator with a subscriber line seize message to the peripheral controller, the peripheral controller for reading the second memory and obtaining the ring cadence indicators associated with the ring type, and ringing a line according to the indicated ring cadence.

Abstract: In a ringer unit driving system for driving a ringer unit provided in common to a plurality of channel units, the ringer unit sends a ringing signal to a communications device via one of the channel units. A signaling bit detection unit, which is provided in each of the channel units, detects a signaling bit contained in a received digital signal applied to one of the channel units and generates a detection signal. A ringer provided in the ringer unit generates the ringing signal. A power source supplies the ringer with power. A switch is connected between the ringer and the power source and is connected to the signaling bit detection unit. The switch connects the power source and the ringer to each other only when the signaling bit detection unit generates the detection signal.

Abstract: A ringing generator includes a binary signal source generating a waveform with eight degrees of freedom controlled to suppress or cancel certain harmonics to produce a binary low frequency signal substantially free of low frequency components other than the desired ringing frequency. The binary signal is amplified and filtered to remove unwanted frequency components above a certain threshold to produce a substantially sinusoidal ringing signal.

Abstract: A telecommunication system comprises a network for transmitting information, a plurality of terminals connected to the network for communicating to each other, a data base provided in the network and having a plurality of storage areas corresponding to the plurality of terminals for storing a plurality of alerting patterns, alerting tone selector for reading, on the basis of information for identifying a calling terminal, an alerting pattern specified at the calling terminal when there is a call incoming from the calling terminal to a called terminal, from a storage area in the data base corresponding to the called terminal, and alerting tone controller for controlling a called terminal on the basis of the alerting pattern and generating a corresponding alerting tone at the called terminal when there is an incoming call.

Abstract: A call signal generating circuit includes a step-up transformer having a primary winding and secondary windings and a first switching circuit coupled between the primary winding of the step-up transformer and a D.C. power source for turning ON/OFF at a frequency higher than a frequency of a call signal. A rectifying circuit is coupled to the secondary windings of the step-up transformer for rectifying voltages induced at the secondary windings into a positive polarity voltage and a negative polarity voltage. A second switching circuit is coupled to the rectifying circuit for alternatively outputting the positive polarity voltage and the negative polarity voltage with a quiescent time in which both the positive and negative polarity voltages are not output. A capacitor is coupled to the second switching circuit for receiving the positive and negative polarity voltages output from the second switching circuit.

Abstract: A circuit assembly which includes an interface circuit between a subscriber line and exchange devices of the kind with two amplifiers connected in a bridge configuration between the battery terminals and having a means of detecting the output currents; a supply circuit which includes the exchange battery and a ring generator; a switch-over means for putting the line through the interface circuit or the supply circuit; two bridge resistors which are in series with the line when the latter is connected to the supply circuit and of which one is connected permanently between one of the line terminals and the output of one of the amplifiers, which output is substantially at the potential of one of the battery poles; an additional resistor, having a much higher resistive value than that of the bridge resistors and being connected between the other of the line terminals and the output of the other of the amplifiers; and a processing means within the interface circuit, which includes said detecting means and is effec

Abstract: A bell signal generating circuit for a key telephone set. A dc component of a pulse signal is removed by a photo-coupler to generate a first signal. A high frequency component of the first signal is removed by a filter to generate a second signal. A differential amplifier amplifies the second signal to generate a bell signal. To the differential amplifier, a dc supply voltage based on the dc signal in synchronism when the pulse signal is applied.

Abstract: A low frequency high voltage AC power for a telephone system is provided by a ring signal generator, which produces a ring signal from a DC power supply using a pair of switches controlled by pulse width modulation (PWM) circuit. The ring signal generator includes a PWM circuit driving a pair of MOSFET transistors via a respective pair of opto-isolators. The output of the MOSFET transistor switches is commonly connected to a low pass filter network. The ring signal generator of the present invention advantageously produces a 65 VRMS ring signal at very high efficiency.

Abstract: A ringing signal generation circuit contains a direct current power source, a transformer, a control transistor, a rectifying and smoothing circuit, an invertor circuit, and an invertor controlling circuit. The direct current power source generates a direct current voltage. The transformer contains a primary winding and a base-driving winding in a primary side, and a secondary winding in a secondary side. The control transistor is connected in series to the primary winding and the direct current power source, and controls a current flowing in the primary winding. The rectifying and smoothing circuit rectifies and smooths a current generated in the secondary winding. The invertor circuit for converting a direct current output of the rectifying and smoothing circuit into an alternating current. The invertor controlling circuit controls the invertor circuit.

Abstract: A first part for picking up a signal being proportional to a ringing tone signal transferred on a subscriber line; a second part for extracting an ac component from the thus picked-up signal; and a third part for receiving both the signals from the first and second parts and comparing, in level, these two signals to produce a ringer stop signal if the level difference therebetween becomes larger than a setpoint value, and thus, a conventional low-pass filter can be removed.

Abstract: A plurality of trunk interface blocks are provided to receive a plurality of telephone lines. In each trunk interface block, a ringing signal detection circuit detects an incoming ringing signal on the corresponding telephone line, and a code insertion circuit inserts in a PCM signal, coded data indicative of whether or not an individual ringing signal exists on the telephone line in response to the output of the ringing signal detection circuit. The PCM signal is transferred through a PCM time division switch and an extension interface circuit to a destination extension set. In the destination extension set, the code discrimination circuit extracts coded data from the PCM signal and controls the on-off circuit to drive the speaker in synchronization with the individual ringing signals.

Abstract: An electronic ringing generator circuit with provision for power efficient current limiting and preservation of sinusoidal or near sinusoidal output waveform under overload conditions. A pulsewidth modulated DC-DC power convertor produces supply voltages for a linear class B power amplifier which has a low frequency low level sinusoidal signal applied to its input through a first controllable attenuator. The DC-DC convertor's reference input is also driven through a second controllable attenuator which is coordinated with the first controllable attenuator. The attenuators are operated in such a way that if the amplifier's output current exceeds a predetermined value, both the input signal and amplifier supply voltages are reduced in a coordinated manner so that simultaneously the output AC waveshape is preserved and the amplifier continues to operate at or very near optimum efficiency. The amplifier may be operated to produce a sinusoidal output (crest factor =1.

Abstract: An added main line system is disclosed with particular utility in connection with equipment for providing the services of two telephone lines on a single conductor pair. The ring generator of the added main line system has two transistor bridges, one for the ringing signal on each of two subscriber lines. In each bridge, diagonally opposed pairs of transistors are turned on in alternation, providing alternating current for the ringing signal. The two bridges, each of which has four transistors, share two transistors. Comparators provide off-hook detection during the ringing cycle. Off-hook detection circuits are provided in series with selected driver transistors of the bridges, so that the condition of customer equipment going off-hook may be detected even though limited power is available for testing for the off-hook condition.

Abstract: A method of automatically and equally distributing the ring load for an exchange system. The subscribers are grouped so that at any one time the subscribers of one group only is supplied with the ring current for ringing the telephone. If the number of the subscribers exceeds the allowable limit within the specified on time, the on time is automatically reset by use of a subtracting time to limit the ring load within a specified value.

Abstract: An encoded telephone signalling apparatus and method provides pleasant, relatively distinct and quickly distinguishable personalized call destination information and distinctive call origin information signals within an audible ringing pattern. The ring pattern or envelope is partitioned into two segments, the first segment providing call destination and identifying which party should answer the call, the second segment providing call origin information. The second segment contains information such as, for example, whether the call is an inside call (intercom), an outside call (central office), or a priority call. Within the first segment, call destination information is encoded in a melodic contour pattern. Within the second segment, call origin information is encoded by varying the number of pulses obtained from a single frequency audio signal which is syncopated to the melodic contour pattern provided by different audio frequencies in the first segment.

Abstract: Within a digital PBX system or the like, an appartaus permits provision of digital composite tone alerting particularly suitable for piezoelectric transducers with one arbitrarily selectable tone, by means of logic circuits for latching the sign-bit in a received PCM signal that exceeds a validity threshold, and by combining the toggling sign-bit with another tone to yield the composite tone.

Abstract: A system transmits information over telephone lines using ring signals. The ring signals have bursts of selectable duration separated by selectable time intervals between bursts. A ring signal translator receives the ring signals from telephone lines whereupon a computer activates selected indicators in response to the particular ring signal.

Abstract: A series ringing signal generator is disclosed which comprises a source of a user control signal. A programmable ringing signal generator is provided for generating an analog sine wave signal having a selectable amplitude and frequency in response to a selection signal. Finally, sequencing means, coupled between the source of the user control signal and the programmable ringing signal generator, is provided for generating a sequence of selection signals in response to said user control signal.

Abstract: A ringing switch for providing ringing voltage and tripping voltage to the cable pairs of a telephone central office. The switch synchronizes the control signal from a cadence generator with the zero crossing of the ringing voltage to ensure that the voltage at the switch output changes from the ringing voltage to the tripping voltage or vice versa only when the ringing voltage crosses the tripping voltage. Field effect transistors are used to switch the ringing voltage and a silicon controlled rectifier is used to switch the tripping voltage.

Abstract: A programmable ring signal generator includes a source of a user control signal. A controlled clock signal generator produces one of a set of respective clock signals responsive to the user control signal. A switched capacitor filter is coupled to the clock signal generator for converting the clock signals to an analog sine-wave. Finally, a power amplifier, coupled to the sine-wave converter, produces the ring signal.

Abstract: A telephone circuit, which may be monolithically integrated, for supplying ringing signals to a subscriber's telephone line and for detecting an off the hook condition during ringing, including a logic control circuit connected to exchange components which control the supply of the ringing signals and determine their rhythm. The logic control circuit is connected to a circuit for detecting direct current on the line and a current comparator for generating a signal when the value of the line current exceeds a predetermined current value. This signal is also supplied to the exchange components via a transfer circuit to inform them that an off the hook condition has taken place. The logic control circuit is connected to a timing signal generator which synchronizes its functions with times in which the ringing signal has a zero amplitude, and is connected to a signal amplifier circuit which supplies the ringing signals to the line and to the transfer circuit.

Abstract: Message signaling device for a telephone installation having analog stations and station equipped for this purpose. The invention has as its objects a signaling device by light means for a telephone installation whose subscribers are equipped with analog stations and the stations equipped for this purpose. Each telephone station (4) concerned is equipped in parallel, on the one hand, with a message lamp (59) in series with a resistor (60), on the other hand, with a capacitor (61), coming out of the rectifier bridge (51) of the station. The message signaling is achieved by action of the control unit (3) of the telephone exchange equipment on the injector (36) of ringing signals assigned to the station, so as to cause it to transmit rhythmic signals which differ from the rhythmic ringing signals by the shorter period of the transmission phases of the signal and which make possible the lighting of the lamp.

Abstract: A telephone circuit, which may be monolithically integrated, for supplying ringing signals to a subscriber's line and for detecting an off the hook condition during ringing includes a circuit for supplying ringing signals coupled to exchange control components for generating a constant frequency sinusoidal signal which gives rise to the ringing signals and an enabling circuit, controlled by the exchange components, for enabling the supplying of the ringing signals to the line and for activating a circuit for detecting a direct current on the line. The circuit for detecting a direct current on the line supplies a signal to a circuit for controlling the detection of an off the hook condition, and which supplies an inhibiting signal for the enabling circuit and check, only after a predetermined time, whether the circuit for detecting a direct current on the line is still supplying a signal and for generating a signal informing the exchange components that the set has been off the hook.

Abstract: In a calling signal transmitting apparatus, a ring trip equipment, including a ring trip detecting circuit for detecting a ring trip signal in response to an off-hook operation of the telephone set during a signal state of an intermittent ringing signal and a loop detecting circuit for detecting a loop signal in response to an off-hook operation of the telephone set during a nonsignal state of the intermittent ringing signal. Also included are a logical OR gate circuit, for providing, as a status signal, a logical sum of the ring trip signal and the loop signal, and a supervising circuit for supervising the status signal.

Abstract: A circuit for sending out a ringing signal of a high voltage and a low frequency to a telephone set through a telephone line repeatedly with a predetermined time interval. In order to omit use of a high power oscillator and relays, a D.C. power supply of a high voltage is operatively connected to the telephone line through phototransistors of photocouplers being driven by a pulse signal having a low voltage and the low frequency under control of pulses occurring at the predetermined time intervals so that the ringing signal is sent out to the telephone set repeatedly with the predetermined time interval.

Abstract: A power amplifier includes negative and positive terminals for connection across a direct current supply, an input for receiving a reference signal and an output for supplying an amplified replica of the reference signal. Positive polarity and negative polarity energy transfer gates are controlled to store electrical energy from the direct current supply, and to subsequently release electrical energy to the output. A control circuit is responsive to the reference signal and a potential amplitude at the output, for controlling which of either or neither of the positive polarity and negative polarity energy gates is active, and for controlling each quantity of electrical energy stored by an active one of the energy gates so that the amplified replica of the reference signal is provided. In an example, the power amplifier is used to efficiently generate ringing battery signals for use in a telephone facility.

Abstract: A digitally controlled ring signal generator includes a plurality of ring signal generating sources providing a plurality of inputs to each of a plurality of ring circuits. Each input is an a.c. signal superimposed on a d.c. bias that is greater than or equal to the peak voltage of the a.c. signal.

Abstract: A personal branch exchange telephone system including improved interface circuitry to couple the system to outside telephone lines as well as to individual telephone sets on extension lines in the PBX system. The PBX system is connected to the telephone lines only through electromagnetic coupling and circuitry is provided to detect both ringing signals and loop current carried by the telephone lines.