Abstract: Any valid displayed called number may be properly visually segmented by a call-processing arrangement (200) that uses stored definitions of syntax (320, 350) and grammar (400, 410) of the whole network numbering plan. The syntax definitions include definitions (312) of individual symbol strings and their associated display demarcations (360), if any--such as spaces or dashes or parentheses--or even their associated replacement strings. Display demarcations or replacement strings that are specified for individual symbol strings are administratively reprogrammable to change the specified display demarcations or replacement string. Following dialing of an individual symbol string, the symbol string is identified and it or its replacement is displayed (986) on the display (19) of the caller's telephone set (17) along with any previously-dialed symbol strings and is demarcated therefrom as specified in the definition of the symbol string.

Abstract: A telephone jack includes a first pair of contact wires for connection to a subscriber premises line and a second pair of contact wires for connection to an incoming telephone company line, a pair of bridging members are mounted for insertion in the jack and into engagement with the first and second pairs of contact wires to interconnect the subscriber premises line and the incoming telephone company line and are for being withdrawn from the jack and from engagement with the first and second pairs of contact wires to disconnect the subscriber premises line from the incoming telephone company line to provide a demarcation point therebetween.

Abstract: A speakerphone system has a speaker and microphone in a common acoustic environment and electrically preceded and succeeded, respectively, by receive and transmit sections and adapted, respectively, to reproduce as sounds by such speaker signals passed through such receive section from a remote station, and to convert sounds sensed by such microphone into signals passed through such transmit section to such station. A computer derives from the signals from the microphone an electric quantity which is a measure of the average audible ambient noise level in such environment, and the computer uses such quantity as one factor among others in switching signal losses between such two sections so as to change the state of operation of the system between transmit and receive states.

Abstract: A low-pass filter is inserted between a two-wire line and a four-wire transmitting line for transmitting a transmission signal supplied from the two-wire line. Input and output signals of the low-pass filter are fedback to a subtracter to provide a subtracted signal which is added to an output signal of a terminal impedance resultant filter. Thus, operation is realized in a stable manner even in a high frequency band, in which an output signal of the low-pass filter is rotated in phase by 180.degree..

Abstract: An echo canceler having an FIR filter for removing an echo from a transmission input signal, the echo resulting from a reflection of a received signal through an echo path, and thereby outputting an output signal with the echo cancelled. The echo canceler includes an impulse response estimating system for estimating the impulse response of the echo path at a time t as a function of the received signal, the echo-cancelled output signal, and an estimated impulse response signal, and thereby outputting the estimated impulse response as the estimated impulse response signal; an echo signal estimating system for generating a predicted signal as a function of the estimated impulse response signal and the received signal, and outputting the predicted signal as an estimated echo signal; and a subtractor for subtracting the estimated echo signal from the transmission signal so as to produce the echo-cancelled output signal.

Abstract: A hybrid circuit includes a two-wire/four-wire conversion unit for forming an interface between a two-wire line and a four-wire line, and a digital balancing unit for canceling a return echo passing through an echo return route including the conversion unit. The digital balancing unit includes first through fourth parts. The first part determines values of elements of a ladder type circuit composed of resistors and capacitors. The ladder type circuit corresponds to an original equivalent circuit having an impedance obtained by viewing the two-wire line from the conversion unit. The second part generates an impedance function of the original equivalent circuit in the form of a z function in accordance with a bilinear transform using an over-sampling frequency. The third part generates filter coefficients of a digital filter by inserting the impedance function into a transfer function of the echo return route.

Abstract: A signal transmission circuit of a telephone system comprises a photo-transistor with its emitter and collector connected to telephone network lines, respectively. First and second relays are disposed, respectively, in the telephone network lines between a primary winding of a voice transformer and the collector and in a line between the base and the primary winding of the voice transformer. When a telephone call arises, the first relay connects the primary winding to the collector of the photo-transistor and disconnects a resistor, which is disposed between a junction of the primary winding and the second relay for connecting the base of the photo-transistor to the junction, from the primary winding so as to transmit voice signals through the voice transformer. When dialing is performed, the first relay is caused to disconnect the primary winding from the collector and connect the resistor to the primary winding, in a closed loop.

Abstract: A visual indicator circuit is provided for visually indicating that a telephone is ringing or that a message is waiting. The circuit includes a visual indicator such as a light emitting diode (LED), a voltage triggering circuit for triggering when a minimum predetermined voltage is applied to the telephone lines, and a current limiting circuit for limiting the current provided to the LED.

Abstract: A digital echo canceller has a receive path (2) and a send path (3) and comprises combining apparatus (10) for forming a send output signal [r(k)] as the difference between the signal [z(k)] applied to the send input (SI) and a replica signal [e(t)] used for cancelling an additive echo signal [e(k)] at the send input (SI) that has developed in response to a receive input signal [x(k)] applied to the receive input (RI), which echo canceller at least includes transforming apparatus (13, 15) for transforming the receive input signal [x(k)] and the send output signal [r(k)]; transforming apparatus (14) for transforming the replica signal [e(k)]; a digital adaptive filter (9) which has a number of filter coefficients for generating the replica signal [e(t)] in response to the receive input signal [x(k)] and the send output signal [r(k)], adaptation apparatus (12) for determining for each block m, adaptation components [A(p;m)] for each of the filter coefficients [W(p;m)] in response to the receive input signal [x(

Abstract: A nonlinear processor for an echo canceller has an adaptive suppression threshold which is a function of an echo estimate signal generated by an adaptive filter. The nonlinear processor also has an adaptive noise transparency threshold which is a function of an estimated level of background noise. The nonlinear processor is in the send path at the near end of a 4-wire circuit, and during far end single talk is activated to pass send path signals that are below the noise transparency threshold level and above the suppression threshold level. The dual adaptive thresholds of the nonlinear processor during far end single talk result in removal of residual echo from the send path while allowing limited levels of actual background noise to remain on the send path to improve the perceived quality of the voice connections to a far end talker/listener.

Abstract: A control circuit for automatic elimination of telephone line noise, a reference tone selecting device for selecting the tone signal on the telephone line; a mode switching device for switching registration of noise pattern and operation of speech transmission; a noise pattern outputting device for outputting and storing frequency spectrum pattern in accordance with noise element coming on the telephone line during the noise pattern registration pattern; and a noise eliminating circuit for eliminating noise element from the transmission signal on the telephone line in accordance with the frequency spectrum pattern.

Abstract: A dial controllable conditionally operative device which is directly connectable to the ring and tip lines of a subscriber loop. "On-hook" coupling is provided to allow the device to provide the conditional operation of one or more of the functional capabilities of a standard telephone. The device is usable in parallel with at least one standard telephone to provide a controlled telephone system. The device may also be usable in an intercommunication system using the ring and tip lines of the subscriber loop.

Abstract: Apparatus and method for communicating a call answered event and other communication services selection information to a call originating device (telephone). Tone signalling technology (DTMF) is used to indicate call progress. DTMF signals are generated by the switching system or associated telephony equipment.

Abstract: A digitally programmable attenuator balances impedance across a two to four-wire hybrid to reduce echo. The hybrid can interface a two-wire bi-directional telephone line, used for both transmit and receive signals with four-wire circuits having separate unidirectional transmit and receive signal paths. The four-wire circuit interfaces the two-wire circuit through a transformer. Optimum isolation is obtained by setting impedance Z.sub.BAL equal to the impedance of the line including the transformer (Z.sub.LINE). The invention eliminates manual or customized individual adjustment of Z.sub.BAL by a set up technician by use of a digitally controlled attenuator to electronically vary the value of Z.sub.BAL in a highly precise fashion. The programmable attenuator provides an input voltage to a buffer voltage-follower amplifier. The output of the follower amplifier is coupled to a known impedance to limit current flow through the impedance and consequently, current flow through Z.sub.BAL.

Abstract: A small portable self-contained, battery powered consumer premise call management device adapted to be connected to a telephone network termination node on a premise to provide audible monitoring of signals on the termination node by depression of a control button. The device includes a battery powered signal lamp triggered by a ringing signal and latched in an on condition until the control button is depressed. The device provides a call notification signal and is usable with and complementary to both network provide and consumer premise equipment providing telephone answering services.

Abstract: A telephone network interface apparatus comprising a cabinet housing a chassis having a planar surface with openings to receive one or more modular terminal panels. The cabinet includes a splicing chamber at one side to receive incoming telephone company cables for connection to the module panel terminals therein. The module terminal panels comprise self-supporting panels carrying protector and electronics fields formed by plug-in type blocks for receiving protector plugs and electronics plugs respectively. A housing encloses the protector and electronics fields and is provided with a lockable door to form a telephone company compartment. Also mounted on the panel is a network interconnection device (NID). The NID is removably attached to the panel by a bracket and mating type connector. The NID includes plug-in jack connections such as RJ11s. The protector and electronics plug-in sockets are wired in series with the NID RJ11 connectors.

Abstract: A method and apparatus for permitting a telephonic device to select the mode of dialing, pulse or tone, which is proper for the local telephone network interface to which it is connected.

Abstract: Method and apparatus for detecting and identifying dial pulse digits in a telephone signal. An embodiment of the inventive method includes the steps of: detecting a dial pulse "0" digit; analyzing the dial pulse "0" digit to determine a predetermined set of data to provide a template which is characteristic of the dial pulse "0" digit; detecting a further dial pulse digit; analyzing the further dial pulse digit to determine a predetermined set of data which is characteristic of the further dial pulse digit; and comparing the predetermined set of data of the further dial pulse digit with the template to identify the further dial pulse digit.