Abstract: A telephone set of distinctive ringing type of a called party capable of generating calling sounds depending upon respective call signals of different patterns received from a remote calling party, including a pattern detector for detecting the pattern of each call signal before the telephone set is connected to the calling party, and a sound generator which operates after the telephone set is connected to the calling party, to generate calling sounds having respective different patterns, depending upon the patterns of the received call signals as detected by the sound detector.

Abstract: Provided is an exchange system accommodating an ISDN circuit as a line wire, in which a channel of the line wire is capable of being selected by an operation performed at a connected telephone. If, in a state where the ISDN circuit has been selected by the connected telephone, a terminating request which has designated the channel in the selected state is received and this terminating request is answered, the selected state on the side of the connected telephone is cancelled. As a result, the operator on the transmitting side can be informed of the fact that the transmitting operation has been interrupted. Further, by denying the received terminating request which has designated the channel in the selected state, a situation in which a transmission from the selected channel can no longer be made is eliminated.

Abstract: An apparatus for use with a cellular telephone to indicate an incoming telephone call to a user includes a cellular telephone battery pack has a circuit that generates a voltage signal with a value representative of the current being drawn from the battery by the operation of the cellular telephone. A status determination circuit monitors the voltage signal and generates a waiting for call state signal whenever the value of the voltage signal decreases from a first selected higher value to a first selected lower value for a first preselected period of time.

Abstract: An apparatus and method for indicating an incoming call that generates a voltage signal with a value representative of the current drawn by operation of the device. A circuit monitors the voltage signal and generates a waiting for call state signal whenever the value of the voltage signal decreases from a first selected higher value to a first selected lower value for a first preselected period of time. An RF detection circuit monitors the status of the device's transmitter and generates a transmitter active status signal whenever RF appears for a selected period of time.

Abstract: A power conservation system for a modem in a computer system having a primary power supply and an auxiliary power supply, including a ring detect circuit coupled to a telephone ring signal line for generating a ring detect signal in response to detection of a ring signal on the telephone ring signal line, a power management system having an input coupled to the ring detect circuit and an output coupled to the primary power supply, the power management system being responsive to the ring detect signal for switching the primary power supply from a first level corresponding to a power conservation mode of operation of the computer system to a second level corresponding to a normal mode of operation, wherein the auxiliary power supply is coupled to the ring detect circuit for supplying power thereto when the computer system is in the power conservation mode of operation, whereby the ring detect circuit is maintained in an active state even during the power conservation mode of operation of the computer system.

Abstract: A telephone system and method for easing an incoming caller's wait time in queue before being connected to a called party is disclosed. A "ready" signal initiated by the called party via the called party's telephone is provided to the caller's telephone to inform the caller that communication can commence between the caller and the called party. Thus, the caller need not wait with the caller's telephone pressed against his or her ear. Instead, the caller can put the telephone down (off-hook) and go about his or her business until receiving the ready signal. The ready signal can be provided visually and/or audibly. The ready signal can be enabled by the caller. The ready signal can also be terminated by the caller to enable the initiation of communication with the called party. "Ready enable", "ready" and "ready termination" functions can be initiated by pressing specialty keys on a telephone or can be assigned predetermined sequences of keys from a traditional telephone key pad.

Abstract: The present invention relates to a method of detecting call progress tones specified in a tone plan, comprised of calculating a power spectrum of a segment of an input signal containing a call progress tone, discriminating, based on the power spectrum, likely frequencies of the call progress tone, determining likely tone plan frequency bands based on between one and three of the frequencies, filtering the input signal in the frequency bands and extracting quadrature components of the input signal thereby, calculating three spectral moments of the input signal from the quadrature components for the frequency bands, and verifying at least one frequency of a call progress tone contained in the input signal based on the spectral moments.

Abstract: A DTMF digit detecting method and apparatus includes signal state identifier (32) for identifying whether the received signal is in a DTMF-digit-detect state, a no-detect high-energy state, or a no-detect low-energy state, digit candidate identification processor (34) for identifying a digit candidate when the presence of a state other than the no-detect low-energy state is detected following a detection of the presence of the no-detect low-energy state for a first predetermined period of time, digit identifier (32) for identifying a DTMF digit corresponding to a sample group in a DTMF-digit-detect state, and valid digit identifier (34) for identifying a valid DTMF digit when at least a first predetermined number of sample groups are all in the DTMF-digit-detect state or in an allowable combination of states.

Abstract: A method and apparatus for detecting a dual tone alerting signal in the presence of speech for the purpose of initiating transfer of special service information on a telephone line is described. The apparatus includes two channels for separately detecting each tone. Each channel includes means for comparing the signaling energy around one of the tones with the energy in a selected weighted guard band portion of the voiceband. Based on this comparison, a determination is made whether a tone is or is not present. A pulse signal formed from the coincidences of tone detection in each channel is used by timing circuitry to determine whether the dual tone alerting signal is actually present or whether speech energy caused both tones to be erroneously detected (talkoff). Characteristics of this pulse signal are analyzed to determine whether an alerting signal is present.

Abstract: Apparatus for detecting single and/or multiple cadenced tone progress status of a telephone call in any one of a plurality of telephone networks is disclosed. A set of parameters for each of a multiplicity of predetermined single and/or cadenced tones in which some call progress status having multiple different sets of parameters for the same call progress status are stored in memory. Parameters of the cadence (s) of a valid tone present on the telephone line are measured and compared with the multiplicity of sets of parameters stored in the memory to establish the presence of the call progress status represented by the corresponding cadenced valid tone. For tones having multiple cadences, the measured parameters of each cadence is compared with a corresponding set of cadence parameters of the memory to establish the presence of the call progress status represented by the multiple cadenced tone.

Abstract: A sensor circuit for telephone line includes a line current detecting circuit (52, 54) which generates a detection signal in response to a line current flowing in a telephone line (20, 22). The detection signal is applied to a first amplifier (56), and the detection signal as amplified is not only further amplified by a second amplifier (57) but also applied to a tone deriving circuit (60) and a CI detecting circuit (61) via a coupling capacitor (59). The detection signal as amplified twice is applied to a comparing circuit (58) which compares the detection signal from the second amplifier with a first reference voltage (V1) and a second reference voltage (V2), so that a line current supervisory signal is outputted from the comparing circuit. The tone deriving circuit includes a band-pass filter and derives a tone signal from the detection signal from the first amplifier. The CI detecting circuit detects a CI (calling tone) on the basis of the detection signal from the first amplifier.

Abstract: Method and apparatus for detecting a far-end disconnect signal for use by telephony applications such as voice messaging systems. In a preferred embodiment of the present invention, signal power of a telephone signal in particular frequency ranges is compared with the signal power in these frequency ranges for characteristic far-end disconnect signals used by telephone systems worldwide. Further, the cadence of the signal power of the telephone signal is examined to determine whether the cadence of the telephone signal is characteristic of far-end disconnect signals, including "busy signals" and "dial tones.

Abstract: In an automatic signaling-system switching device provided in a subscriber line circuit between a communications device and an exchange, the subscriber line circuit has a plurality of signaling-system processing units respectively providing processes suitable for a plurality of signaling systems usable in the subscriber line circuit. A first unit is provided for identifying one of the plurality of signaling systems on the basis of a state of the subscriber line circuit. The signaling systems have respective particular states of the subscriber line circuit. A second unit is provided, which selects one of the plurality of signaling system processing units corresponding to the one of the plurality of signaling systems identified by the first unit.

Abstract: An acoustic feedback suppression device, particularly for auxiliary ringers in plug-in telephone systems, includes diodes in addition to a rectifier bridge of the ringer. The circuit provides direct-current decoupling and limits the AC voltage present across the auxiliary ringer.

Abstract: Voice detector for detecting whether a telephone signal has been produced by a voice. The voice detector obtains, on a per frame basis, measures of the following quantities relating to the telephone signal: total energy; energy and frequency of two largest energy peaks in a frequency spectrum; and signal-to-noise ratio (SNR). If the measure of total energy exceeds a predetermined threshold, the voice detector increments running sums of the following measures: total energy; frequency of the largest peak in the frequency spectrum; and SNR. Until a predetermined number of frames, referred to as a window, has been reached, for each frame, the voice detector determines whether the telephone signal was produced by ringing (incrementing a ring count if it was) and whether there is a local energy maximum (incrementing a local energy maximum count if there was).

Abstract: The present invention automatically initiates a telephone call to a given destination. At the same time, the progress of the call is monitored. The time of a ring back and voice answer received from the destination are recorded to an output file. At the end of the voice answer, a pre-recorded voice message is sent by the system to the person answering at the destination. Thereafter, the recorded data is used to determine the response time for that particular telephone destination. A plurality of destinations can be tested. A second embodiment of the present invention provides for the interactive correspondence between a remote evaluation unit and a called destination and the measurement of the performance characteristics of the telephone network.

Abstract: A technique for software ring tone detection is disclosed utilizing, in the preferred embodiment, a recursive algorithm. The technique provides flexibility in that a digital signal processor may be reprogrammed to detect ring tone frequencies and amplitudes present in numerous different countries.

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 DTMF signal receiving apparatus includes a DTMF signal receiver; and a DTMF signal judging circuit. The DTMF signal receiver includes an input section for receiving an input signal from an external apparatus; a plurality of first band-pass filters connected to the input section; a plurality of second band-pass filters connected to the input section; and an output section connected to the plurality of the first band-pass filters and the plurality of the second band-pass filters, for outputting a code based on a plurality of outputs from the plurality of the first band-pass filters and the plurality of the second band-pass filters.

Abstract: Provided is an exchange system accommodating an ISDN circuit as a line wire, in which a channel of the line wire is capable of being selected by an operation performed at a connected telephone. If, in a state where the ISDN circuit has been selected by the connected telephone, a terminating request which has designated the channel in the selected state is received and this terminating request is answered, the selected state on the side of the connected telephone is cancelled. As a result, the operator on the transmitting side can be informed of the fact that the transmitting operation has been interrupted. Further, by denying the received terminating request which has designated the channel in the selected state, a situation in which a transmission from the selected channel can no longer be made is eliminated.

Abstract: A ringing tone signal detecting circuit detects a ringing tone signal from a received signal of the echo canceler type which is supplied from a subscriber line through a hybrid circuit. The ringing tone signal detecting circuit has a sampler for sampling the received signal at a predetermined sampling frequency, a comparator for comparing an output signal from the sampler with a predetermined threshold value and producing a binary digital signal, a plurality of first through nth delay circuits for delaying the binary digital signal from the comparator for 1 through n sampling times, respectively, and a frequency detector for detecting a ringing tone signal from the binary digital signal from the comparator and output signals from the first through nth delay circuits. The circuit has particular use in detecting the ringing tone signals in the 2B1Q signaling code scheme.

Abstract: A telephone circuit is provided for distinguishing between a normal incoming telephone call and a test telephone call. When the telephone is polled from a central station to cause it to undergo a self-test routine, a ringing signal is used which consists of a series of three ringing signals each lasting less than a predetermined time. Consequently, when such a ringing signal is received, a relay remains open so that there is no audible ringing tone. The system thus enables a testing routine to be carried out by the telephone without causing the telephone to ring.

Abstract: A selective ringing receiving circuit comprises a timing generating circuit for generating a timing signal for bit length comparison, a bit length comparison circuit for comparing, in terms of the timing signal, the respective bit lengths of `1` and `0` of a received digital signal outputted in a direct conversion system when a selective ringing signal is received from a base station, thereby producing a changing point detection/selection signal, a changing point detection circuit for selecting the rising and falling changing points of the received signal using the changing point detection/selection signal to produce a detected rising or falling changing point signal of the received digital signal, and a bit synchronization circuit for performing bit synchronization in response to the detected changing point inputted.

Abstract: Device for detecting and identifying call progress tones on telephone lines. The application discloses a device for converting auditory call progress tones to visual indications and a novel circuit for identifying and distinguishing call progress tones based on their on-off cadence, if any, along with various alternative embodiments including: (1) a device which converts call progress tones to visual indications as for use by the deaf, (2) a device which is programmed to automatically go off-hook at certain times, detect a tone such as a stuttered dial tone indicating a message waiting, and activate a visual indicator, and (3) the use of a capacitor or rechargeable battery which is periodically refreshed by the device automatically going off-hook and which, while the device is on-hook, provides power required by the device.

Abstract: Dial tone detection circuitry is employed in a telephone of the type which has its dialing mechanism incorporated into the handset. The dial tone detection circuitry is connected to an annunciating means which indicates to a user that dial tone is present without the need to bring the handset to the user's ear. The dial tone detection circuitry my also be connected to the telephone's automatic redial circuitry to ensure efficient operation of the redial function.

Abstract: A signal detecting device capable of determining whether automatically dialling transmission is to be carried out by detecting an identification signal sent from an exchange system via a telephone line. The frequency variation of the identification signal is constant since the identification signal is a composite wave of a plurality of constant frequency signals. A pulse train having substantially a constant number of pulses can be obtained by comparing the level of the identification signal provided from the telephone line with a predetermined reference voltage by voltage comparators. Frequency counters count for a constant time period the number of pulses included in the pulse train provided from voltage comparators. According to the count result output of frequency counters, a determining circuit makes determination whether an identification signal is received or not.

Abstract: A called party response detecting apparatus of a terminal equipment includes a plurality of filter units, a determining unit, and an analyzing unit. The filter units are commonly connected to an input side and detects specific frequency components included in a plurality of signal tones coming from a telephone line. The determining unit checks the presence/absence of each output from the filter units for each fundamental period to determine a signal type on the basis of a predetermined output pattern. The analyzing unit analyzes various signal tones and a called party response on the basis of occurrences of signal type outputs during a predetermined time period of the determining unit.

Abstract: Method and apparatus allows accurate detection of voice presence on a digitized communication line even in the presence of tone signals. The method includes analyzing digitized communication input signals by current blocks of 20ms, to define the stationary or non stationary state of any current block. Then an analysis on the states of the M last 20ms blocks allows the final decision on voice presence.

Abstract: A terminal connection device changes and connects a plurality of terminals to one telephone line according to kinds of ringing signal sequences sent through the telephone line. The terminal connection device comprises switches connecting between the telephone line and the terminals, a control circuit commanding ON/OFF operation of the switches, and a photo coupler converting the ringing signal obtained through the telephone line into light signal and inputting the light signal to the control circuit. The control circuit includes a device for judging as to whether a ringing signal sequence sent through the telephone line is the same as the sequence data or not.

Abstract: A multiple phone ring boost circuit rings multiple subscriber telephones synchronized with a ring signal sent from a telephone company central office is connected to multiple subscriber telephones. A local generator creates a local ring signal, and a local generator sensing circuit determines if the local generator is functioning properly. A ring sensing circuit senses if a ring signal is being received. A switch connects the line leads to the subscriber leads in a first position, and connects the local generator to the subscriber leads in a second position. A control circuit varies the switch between the second and first positions. When the ring sensing circuit detects an incoming ring signal and the local generator sensing circuit detects a properly functioning local generator, the switch is placed in its second position. When the ring signal pauses, the control circuit places the switch in the first position.

Abstract: Radio telephone equipment having a sounding device, a sounding device drive circuit for driving the sounding device, and a control circuit for controlling the sounding device drive circuit. When a person manipulates the equipment to originate a call, the equipment interchanges various control signals with a base station to set up a channel for communication. Then, the base station sends to the equipment a control signal indicative of the fact that the other party has responded to the call. In response, the equipment causes the control circuit to activate the sounding device drive circuit which in turn generates a predetermined alert tone to show the user that a conversation is allowed to be held.

Abstract: A central clock unit has a ring generator for generating ringing signals and a DC voltage source for generating display signals. With the assistance of the central clock unit having a switching unit that is controlled by a central processor unit, either the ringing signals or display signals are transmitted to an analog communication terminal via a ring down line and a line connection unit. Within the line connection unit, a switch is controlled by a ringing-display procedure to generate the desired rhythm of the ringing or display signal. A read/write memory unit within an I/O device is divided into dedicated memory sections to eliminate any delays associated with the control of the ringing-display procedure. The dedicated memory sections are used to store information which is written to or read from the memory by the I/O device and the central processor unit.

Abstract: Modular hold circuits which may be independently connected to a telephone line and powered therefrom are provided in accordance with the teachings of the present invention. Hold circuits connectable to a telephone line in the same manner as a telephone instrument are employed to detect an actuating signal generated at any telephone instrument in an off-hook condition connected to that telephone line. Upon detection of such actuating signal, an impedance is placed across the telphone line to establish a hold condition. The hold condition established may be released by placing any telephone instrument connected to a telephone line in an off-hook condition, however, if the telephone line is provided with a "call waiting" feature, such off-hook condition must be maintained for an interval exceeding that associated with a "call waiting" signal for the hold condition to be released.

Abstract: An analog communication signal such as the signal transmitted over a telephone line is converted to digital form for storage in the memory of a computer. Segments of the digital representation of the signal are analyzed to determine whether or not the signal has uniform frequency components repeating at regular intervals. Detection of such regularly repeating uniform frequency components is useful in an automated telephone system to determine whether a telephone signal consists of voice or a call progress signal.

Abstract: There is disclosed a tone type recognition method capable of recognizing a call progress state of a central office line switching system by using a tone detector. The method enables the system to correctly recognize the type of call progress tone, regardless of its frequency, by conducting periodic detection of characteristics of cadence classified by tone-type.

Abstract: A call progress monitor and algorithm for placing a phone call over the phone lines. The algorithm is hierarchically arranged having three major routines or portions: tone detection, signal recognition and situation recognition. Based upon the definitions stored in a memory and the commands, the call progress monitor algorithm is applied to the telephone audio data. The call progress monitor algorithm is controlled by a host computer which sends a Recognize Situation Command and expects to receive some time later, a Recognize Command Termination Report. The tone detection portion of the algorithm measures the power at each of a predetermined number of frequencies of interest. The signal recognition portion of the algorithm detects the presence of a particular signal. A signal is a particular tone or set of tones that are uniquely present (while all other tones are absent).

Abstract: An amplifier in a housing for receiving and detecting the presence of portable paging devices that produce an audible signal when activated. The amplifier allows the connection of a large capacity annunciator or visual alarm. Circuitry is provided to connect the output of the amplifier to the bell of conventional telephone sets without affecting its normal operation. The telephone set bell can be activated with a voltage signal different from the one it normally generates so that a user can distinguish the two calls.

Abstract: Apparatus for recognizing a telephone call supervision signal by comparing its frequency and cadence to the frequency and cadence of a previously learned call supervision signal is provided as part of call completion equipment (10). Call progress tone detector (50) receives a call supervision signal and responds by outputting frequency parametric signals which indicate whether predetermined standard frequencies are present in the received signal. Microprocessor (74) determines the cadence of the received call supervision signal and outputs a corresonding cadence parametric signal. If it is beneficial to learn the received call supervision signal, the frequency and cadence parameters are stored in memory (78). Recognition circuits can then recognize a subsequent telephone call supervision signal by comparing its frequency and cadence parameters to the frequency and cadence parameters stored in memory (78) for at least one learned signal.

Abstract: A method is disclosed for monitoring call setup communications between a communications station and a telecommunications network. A plurality of so-called "result codes," each consisting of a numeric prefix and an associated textual message, are transmitted from the telecommunications network in response to an attempted call setup. These result codes are screened at the communications station by matching numeric prefixes against a predetermined list of selected numeric prefixes and to eliminate irrelevant and/or redundant messages. Next, an alphanumeric display is utilized at the communications station to display in a user discernible manner all those messages indicative of the status of call setup information.

Abstract: A pulse detector system for reliably counting pulse signals generated by calling party telephone dials. The system includes generating a dial pulse template based on a sample train of pulses. A preferred embodiment uses a pulse amplitude template comprising an amplitude histogram.

Abstract: A called party response detecting apparatus includes a plurality of filter units for respectively detecting natural frequency components included in a plurality of signals sent from a telephone line. The apparatus also includes switching units for switching input levels of the filter units in a plurality of steps and a continuous signal detector for detecting that a logical sum output from the filter units has continued for a predetermined interval of time. An input level control unit operates to control the switching units to set an input level at a lowest level while waiting for a signal and also to reset the input level at a predetermined level different from the lowest level when an output is obtained from one of the filter units. During this reset operation, the input level control unit decreases the input level in steps until an output is obtained from the continuous signal detector.

Abstract: The present invention is directed to a method and system which is automatically responsive to transmitted DTMF signals containing messages received from, and corresponding to respective calling originators. The invention provides an indication to the user of message storages areas which are used or available. If all message storages are full, an alarm function is provided. The system also provides an automatic dial capability wherein the number dialed is retained in memory only if the call is not completed.

Abstract: A method for detecting the presence of a predetermined dual tone signal on a conductor including steps of performing threshold detection on the conductor for detecting the presence of signals having an amplitude greater than a predetermined threshold signal, and in the event of detection of a signal having substantial amplitude, detecting the periods of a predetermined number of successive cycles of the signal, and in the event the successive detected periods are different, detecting an average value of the periods. In the event the average period corresponds to a frequency equivalent to the average frequency of the predetermined dual tone signal, an output signal is generated indicative of the presence of the dual tone signal. This method can advantageously be used for detection of dial tone on a telephone conductor. A method is straightforward and can be easily implemented by a microprocessor program in conjunction with simple threshold detection circuitry.

Abstract: A dial tone detector is provided possessing a precise definition of a passband. In one example, virtually infinite roll off is achieved in less than 5 hertz. An incoming analog signal of at least a predetermined amplitude is limited to produce square wave pulses which are counted in a first counter over a period of time determined by a periodic RESET signal. A READ signal occuring just before the RESET signal causes either a valid count state or an invalid count state to be stored depending upon the value of the count in the first counter. When a valid count state is in storage, a second counter counts timing pulses while the valid count state persists, whereby in the second counter a count of greater than a predetermined number indicates the presence of dial tone.

Abstract: A modem which can detect an incoming call and provide an indication of the incoming call to a host computer while the power to the modem is turned off, comprising a switchable power supply that can be turned on and off by a remote input from the host computer, a ring detector circuit that monitors for incoming calls and notifies the host computer through an open drain output without using power from the computer, and isolator circuits that provide isolation on all the input/output lines between the modem and the computer to prevent power leakage from the computer's power source when the switchable power supply is turned off.

Abstract: An adapter circuit and system for coupling a telephone answering machine to two telephone lines. The adapter may be set so that the telephone answering machine will answer one or the other of the telephone lines, as determined by setting a mode selector switch to an "automatic" position; so that the telephone answering machine will answer only one of the telephone lines as determined by setting the mode selector switch to a "Line #1" position, or so that the telephone answering machine will answer only the other of the telephone lines by setting the mode selector switch to the "Line #2" position.