Abstract: This invention discloses a telephone network interface enclosure comprising a telephone company compartment having a cover therefor and a telephone subscriber compartment having a cover therefor. A network termination module containing a protector element is disposed in the network interface enclosure. One end of the network termination module is secured in the telephone subscriber compartment while the other end is secured in the telephone company compartment.

Abstract: The invention relates to a credit card dialing apparatus for use in automatically dialing account numbers, security codes and phone numbers into telephones. The apparatus includes a credit card size device having a memory, encoder, speaker, microphone and switch embedded into a circuit board for inputting and outputting specific information depending on the use of the card. The circuit described accesses the account by tones or signals fed through the receiver or direct data input from a small databus. In another embodiment, a microprocessor unit having a keyboard, microprocessor memory, encoder, a speaker unit and microphone as well as an alphanumeric display is utilized. This system permits the user to input the desired numbers and provide serial dialing and identification for particular sources.

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: The present invention provides a method and apparatus for detecting control signal information for an element of a communication system. The control signal information is included in one or more segments of a signal communicated over a communication system channel. The invention provides for the application of a plurality of tapers to a segment of a communicated signal; the transformation of a tapered segment; the determination of a similarity score based on a transform of a tapered segment and a model of a control signal; the identification of control signal information based on a similarity score; and the creation of an indicator signal representative of the identified control signal information to the communication system element. The control signal information may comprise a dual-tone multi-frequency signal. The tapers may comprise a discrete prolate spheroidal sequence. A similarity score may be determined based on a ratio of energy distributions.

Abstract: The potential impedance mismatch of digital terminal equipment and a line test unit that has been equipped to conform with the Bellcore standard of terminating the line with a 600-900 ohm impedance during data reception is addressed by modifying the craftsman's test unit to include a controllably disabled AC impedance, which is operative to normally bridge the tip and ring leads of the telephone circuit under test with the required (600-900 ohm) impedance during data reception and, under direct control by the craftsman's keypad or software control resident in the test set's microcontroller, to selectively remove the AC matching impedance that would otherwise bridge the line. The AC impedance is comprised of a D.C. blocking capacitor and a resistor coupled in series with a controllable solid state relay which is normally rendered conductive during data reception to bridge the tip and ring leads.

Abstract: Speech signals appearing at the receiving and transmitting paths of a speakerphone which operates under voice switching, are received at a control circuit. The control circuit issues a control signal which assumes a first level in the event that a signal at the receiving path exceeds a signal at the transmitting path and which assumes a second level if the signal at the receiving path falls below the signal at the transmitting path. Communication loss is inserted in both the receiving and transmitting paths in response to the first level of the control signal, and is eliminated therefrom in response to the second level of the control signal.

Abstract: Apparatus for reducing the risk of undesirable drifting of the parameters, so-called bursting, of an adaptive echo filter which is coupled between a receiving branch and a transmitting branch included in a four-wire loop. A difference signal (E) which contains no echo from the receiving branch is generated in the transmitting branch in a known manner. The apparatus includes an adaptive predictor filter which is coupled between the transmitting branch and the receiving branch and which functions to generate a compensation signal from the difference signal (E) when transmitting narrowband signals from a near-end. The compensating signal is subtracted from a signal which appears in the receiving branch and the predictor filter is updated in a manner to minimize the correlation between the difference signal (E) and the input signal (X') of the echo filter.

Abstract: A subscriber line interface circuit, coupled between a telephone unit terminal and a switching system, includes a coding and decoding circuit for controlling analog voltages inputted thereinto and outputted therefrom, using a direct current bias voltage, and an interface circuit. The interface circuit has an amplifier for detecting the analog voltage output, a unit for detecting a direct current bias voltage of the analog voltage output, a subtracting unit for determining the difference between the detected analog voltage output and the detected bias voltage, and resistors for driving the telephone unit terminal on the two-wire side. The analog voltage and the direct current bias voltage output terminals of the encoding and decoding circuit are directly connected with the input terminal of the amplifier for detecting the outputted analog voltage and the interface circuit, respectively, so that only a desired alternating current signal is outputted to the telephone unit terminal on its two-wire side.

Abstract: A telephone line repeater (28) includes a pattern decoder/recognizer (100) which recognizes, inter alia, an input interrogating signal transmitted on a telephone network (20). The interrogating signal includes an address field (302) having at least one subfield (304) therein. The pattern decoder (100) determines that its repeater (28) is to be tested, if a predetermined subfield (304) of the interrogating signal is configured according to a predetermined select convention. When the repeater (28) recognizes that it is being addressed, a controller (110) causes the addressed repeater to "loop back", returning, in alternating sequence, test-indicative no-operation signals and diagnostic information ("DSM") signals generated by the repeater. Methods for testing a repeater and methods for testing telephone networks are also disclosed.

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 disable tone detection method for an echo canceller, in which the disable tone signal is within a predetermined tolerance range from a nominal frequency and includes phase inversions occurring at predetermined intervals. The method includes the steps of a) removing frequencies outside the tolerance range from an input signal (S.sub.in, R.sub.in) by band-pass filtering (33), b) sampling (34) the filtered signal at a sampling frequency, the sampling frequency being about half of the nominal frequency, so as to alise the sample signal to the vicinity of the zero frequency, c) creating a substantially in-phase version of the aliased sample signal component, d) delaying the in-phase version by about 2n sample signal periods, where n is a positive integer, e) detecting (34) a phase inversion in the disable tone signal using an XOR operation executed on the aliased sample signal component and the delayed version thereof.

Abstract: A procedure and device are described for cancellation of the echo produced in telephone connections with electrical time-variant characteristics such as for example those affected by phase roll. The echo canceller obtained in accordance with the procedure which is the object of this invention produces an estimate of the echo signal by means of appropriate digital filtering of the signal originated by the far-end talker. The estimated echo is then subtracted from the actual echo. Filtering is activated by an IIR digital filter whose adaptive coefficients are updated by use of an adaptive algorithm based on decimation of the square error. The high convergence speed of said algorithm in the calculation of the coefficient correction step allows a correct estimate of the echo even in case of connections affected by phase roll.

Abstract: This invention discloses a telephone network interface enclosure comprising a telephone company compartment and a telephone subscriber compartment. Disposed within the telephone company compartment is a metal grounding strip. There is a network termination module disposed within the telephone network interface enclosure. The network termination module is partially disposed in both the telephone company compartment and the telephone subscriber compartment. The network termination module contains a protector element, subscriber terminals and a means for grounding. The subscriber terminals are located in the telephone subscriber compartment. The means for grounding is located in the telephone company compartment. and is connected to the metal grounding strip.

Abstract: A focusing apparatus for a video camera or the like in which a change-over between automatic focusing and manual focusing is possible includes an endlessly rotatable and hand-worked manipulator, a detector for detecting the direction and amount of manipulation or rotational movement of the manipulator, and a controller/driver for moving a part of the optical elements in an optical system along its optical axis direction in a direction corresponding to the direction of manipulation of the manipulator detected by the detector and by a distance corresponding to the amount of manipulation of the manipulator detected by the detector, thereby taking the focus.

Abstract: A telephone apparatus includes a digital exchange unit and at least one digital telephone terminal connected to the digital exchange unit. The at least one digital telephone terminal generates monitoring signals and has multiple functions. All of the monitoring signals generated in the at least one digital telephone terminal are forwarded directly to the digital exchange unit. All of the functions of the at least one digital telephone terminal are controlled directly by the digital exchange unit through corresponding control signals.

Abstract: A telephone communication enable state maintaining circuit is disclosed, and the circuit includes a communication circuit 10, a communication operating circuit 20 and an operation maintaining circuit 30. The communication circuit 10 includes contacts 3,4,5, and a condenser C.sub.1. The communication operating circuit 20 includes a resistor r.sub.1, a condenser C.sub.2, a transistor 6 and contacts R.sub.3 a, R.sub.3 b, R.sub.1 a, R.sub.1 b. The operation maintaining circuit 30 includes contacts R.sub.1 c, R.sub.3 c, a resistor r.sub.2, a condenser C.sub.3, and a transistor 7. According to the present invention, telephone calls from the outside can be received, even if the telephone receiver is placed in an abnormal manner.

Abstract: A vandal resistant, remotely programmable voice communications unit is capable of being programmed for automatically calling predetermined telephone numbers. The unit is programmed remotely from any touch-tone telephone. A vandal-resistant push-button actuator employs first and second axially spaced apart, slidable seals on a push-button mounted within a housing. The seals absorb transverse blows to a raised portion of the push-button and a lubricant is disposed between the seals to prevent an adhesive inserted by a vandal from disabling the actuator. A speaker and microphone baffle utilizes offset passageways to inhibit the introduction of a pointed object therethrough to prevent damage to the speaker or microphone. A raised push-button actuator is disposed inwardly of an escutcheon and shaped to form a concave, ring-shaped surface therewith, thus to inhibit damage to the inner surface of the escutcheon from a hammer blow.

Abstract: A retrofit circuit for communication one of three conditions from a line interface unit (LIU) to a receiver unit (RU), using only one external connection between the LIU and the RU. The LIU has a detection circuit and two resistors. The RU has a voltage comparator. The detection circuit outputs a first input signal in response to a signal having ESF and no yellow alarm, a second input signal in response to a signal having ESF and yellow alarm, a third input signal in response to a signal having SF with no yellow alarm, and a fourth input signal in response to a signal having SF with yellow alarm. The resistors output to the external connection a first voltage level in response to the first and third input signals, a second voltage level in response to the second and third input signals, and a third voltage level in response to the second and fourth input signals.

Abstract: A line interface circuit for coupling signals between a telephone line and a hybrid circuit includes a loop driver circuit for supplying energizing current to the telephone line and for driving the telephone line with alternating current signals. A loop current detector connected in series between the telephone line and the loop driver circuit, generates a voltage signal in response to current flow in the telephone line. Amplifier circuits are arranged to be responsive to differential signals on the telephone line, and to signals from the hybrid circuit, for generating a composite signal. The composite signal and the voltage signal are combined in a network having an output connected to control the operation of the loop driver circuit so that the telephone line is terminated with a preferred impedance.

Abstract: An autoequalizing hybrid circuit for providing a cancelation path to minimize the two-wire receive path signals that are reflected onto a two-wire transmit path from a subscriber line interface circuit is disclosed. The hybrid circuit includes a variable impedance balance network. A tone generator injects a set of equalization signals into the receive path which are used to control the setting, or equalization, of the balance network. The tone generator also generates a supervisory signal into the receive path used to monitor the performance of the balance network. A detect circuit monitors the level of the reflected equalization sidetone signals and produces balance signals whenever the equalization signals fall to a null level. The detect circuit also monitors the supervisory sidetone signals and produces a recalibration signal whenever an abrupt change in the signals indicates that the balance network is no longer adequately cancelling their reflected signals.