Abstract: A broadband network, such as a cable television (CATV) system, for two-way digital communications between a headend and a number of remote terminals dynamically adjusts the power of the upstream signal transmitted by each remote terminal to maintain the bit error rate (BER) of the upstream signal received by the headend below a predetermined limit. In particular, each remote terminal includes a data receiver for receiving signals from the headend (including control signals), and a data transmitter for transmitting digital data signals upstream to the headend. The power level of the data transmitter can be adjustably controlled by the control signals from the headend.

Abstract: A data link access unit for insertion into a T1 span supporting the extended superframe (ESF) format includes an interface for accessing the frames of digital data carried by the T1 span in ESF format (including the data link bits) and calculating performance monitoring data for the T1 span. The interface is controlled by a processor that can access this performance monitoring data and also communicate message data over the data link channel via the interface. Additionally, the unit can provide an ESF/SF interface when inserted into a T1 span between a first channel bank supporting ESF and a second channel bank that does not support ESF.

Abstract: A cable television (CATV) system is modified to provide two-way telephone communications in a subsplit band below the video signal, preferrably in the range of approximately 5-40 MHz. Each line amplifier in the coaxial cable network is equipped with a bypass strap or bypass circuitry to maintain a signal path through the line amplifier for the telephone signal in the event of failure of the line amplifier. Due to the decreased attentuation resulting from its lower frequency, the telephone signal can typically travel the distance of three or four line amplifier spacings without amplification. Line amplifier failure is a common occurrence in CATV networks. Therefore, the present invention greatly increases the reliability of telephone communications over CATV networks.

Abstract: A system for supervising a telephone connection using over a pulse code modulated carrier network between a first customer's equipment and a second customer's equipment. A first channel unit is located in a channel bank serving the first customer's telephone equipment. A second channel unit is located in a channel bank at a remote central office that is geographically remote from the first customer's equipment. The second channel unit is coupled to the second customer's equipment through a switch at the remote Central Office. The second channel unit includes a means for detecting a reverse battery signal generated by the Central Office when the second customer's telephone goes off-hook, and a means for converting the reverse battery signal into a digital supervisory signal. The second channel unit transmits the digital supervisory signal, preferably using the A and B signalling bits on a pulse code modulated carrier system.

Abstract: A two-way broadband audio telephone communications system using 2B1Q line coding between a program amplifier located at a remote site and the central office. The program amplifier includes a codec to convert analog audio signals to digital data at a predetermined sampling rate, and a 2B1Q transceiver to convert the digital data into 2B1Q signals. The program amplifier communicates with a channel unit in the central office channel bank over a conventional two-wire link. This channel unit includes a 2B1Q transceiver that translates the 2B1Q signals received from the program amplifier into PCM format compatible with the T1 carrier system. In order to provide wide bandwidth, the channel unit is allocated at least two channels in each T1 frame. The central office channel bank can communicate with any other similarly equipped channel bank over the T1 carrier.

Abstract: The no balance duplex signalling circuit eliminates the need for setting balance resistors and capacitors to match or be proportional to cable resistance and capacitance as was required of previous duplex signalling circuit designs. A microcomputer is also used to evaluate the output of a simple loop current and voltage sensing circuit to dynamically determine the signalling state of the far end of the trunk conductors. The microcomputer stores a plurality of data which indicate signalling thresholds for all possible duplex signalling states. The microcomputer can then compare the measured voltage and current on the trunk conductors to automatically make a determination of the signalling state based on the stored data indicative of permissible signalling states.

Abstract: A method of providimg two-way communication between a plurality of channel units in a channel bank and a line interface circuit of a telephone system utilizing a receive direction protocol and a separate transmit direction protocol. The receive direction protocol identifies the channel unit to which provisioning data is to be delivered, increases the bandwidth of the voice data region in the time slot corresponding to the identified channel unit, superposes the provisioning data in the time slot with the voice data, and delivers the superposed data to the channel unit wherein the provisioning data is separated from the voice data. The transmit direction protocol utilizes the A and B signaling bits corresponding to the eighth bit of an identified time slot in the sixth and twelfth transmit frames wherein two bits of an eight bit status message is delivered on every other superframe. The two-way communication protocols occur without affecting or interfering with the PCM voice data.

Abstract: A programmable universal signaling circuit for use in a universal channeling unit of a telephone network. The programmable universal signaling circuit uses a line converter and decoder circuit which under control of a microprocessor generates a unique set of configuration signals for configuring the universal signaling circuit into one of a plurality of standard signaling telephone circuits. The universal signaling circuit can be reconfigured either at the location of the universal channel unit or remotely.

Abstract: A system for testing 2B1Q private line data telephony circuits having 2B1Q modulation between the network channel termination equipment and the channel unit. 2B1Q modulation is provided over a single pair of wires connected to the E and M leads of the channel unit. The system can deliver testing signals from two different sources. The first source is from a remote testing system connected to a remote access system which in turn is connected to the T, T1, R, and R1 output leads of the channel unit. The remote testing system generates conventional testing signals which are converted into digital signals for directly communicating with the 2B1Q pair of wires. The remote testing system delivers conventional tests for testing the loopback of the channel connected to the single pair of wires and to the network channel termination equipment. Under a second source of tests, the interface of the present invention directly connects to the T1 carrier.

Abstract: A sealing current generator for a telephone circuit provides a conventional nominal DC bias current in a telephone loop, and also temporarily provides a higher "zap" current whenever the DC current path is broken and then reapplied to the telephone loop. During the "zap" period, the voltage placed across the telephone loop is progressively increased in a number of predetermined steps if the current actually measured in the telephone loop fails to exceed a minimum value. The voltage is then maintained at its last level for the remainder of the "zap" period, after which the device returns to its base mode of providing a nominal DC bias current to the telephone loop.

Abstract: A smart data station termination ("DST") uses a method for remote alignment in which the switched access remote test system ("SARTS") sends a test tone of a single, predetermined frequency and power level to the receive-in port of the DST. The DST amplifies this test tone by a fixed gain factor (e.g. 4 dB) and then progressively increases attenuation (e.g. by 0.1 dB increments) of said amplified test tone until the resulting signal supplied to the receive-out port of the DST is reduced to a predetermined power level (i.e. -16 dBm). After alignment, the attenuation factor remains constant during normal operation of the DST. The preferred embodiment also provides a transponder mode of operation in which test signals received from the SARTS through the receive-in port of the DST are routed through an automatic gain control ("AGC") amplifier and transmitted back to the SARTS at a substantially constant level through the transmit-out port of the DST.

Abstract: The universal channel unit includes a channel interface circuit that uses a pair of fixed ratio transformers to terminate both two wire and four wire analog transmission facilities on a selectable basis. The universal channel unit also includes a plurality of signalling circuits, each of which is switchably connectable via the channel interface unit to provide a DC signalling interface to match the signalling format required by the associated analog transmission facility. The signalling circuits include: DX, FXO, FXS, and other DC signalling circuits. The AC component of the signals carried by the analog transmission facility is output to an adaptive impedance and balance circuit which functions to closely match the impedance of the analog transmission facility and minimize signal reflections under control of a microprocessor. This impedance and balance network is connected to a PCM interface that includes an adaptive echo canceller circuit as well as equalization and gain control circuits.