Abstract: An new cellular interface directly couples the speaker and microphone of a cellular telephone to a simultaneous voice and data (SVD) modem. This interface allows a cellular telephone user to use their cellular telephone for simultaneous voice and data communications over the cellular network. In addition, of the SVD modem has a port coupled to a switched facility of a switching system, this cellular interface allows the cellular telephone user to place a telephone call from their cellular telephone over the switched facility.

Abstract: A simultaneous voice and data (SVD) communications system includes an SVD modem at either endpoint of the system. Each SVD modem provides an SVD signal to the opposite endpoint, where this SVD signal includes both a voice channel and a data channel. One, or both, of these SVD modems allows the respective user to alter either the voice signal that is provided to that user, or the voice signal that is transmitted from that user, via the voice channel of the SVD signal, to the opposite SVD endpoint.

Abstract: A number of arrangements and methods that achieve concurrent communication of analog information and digital information. In general terms, when the communication channel is viewed as a multi-dimensional space, the digital information signal is divided into symbols, and the symbols are mapped onto the signal space with a preset distance between them. The analog signal, generally limited in magnitude to less than half the distance separating the symbols, is converted to component signals and added (i.e., vector addition) to the symbols. The sum signal is then transmitted to the receiver where the symbols are detected and subtracted from the received signal to yield the analog signal components. The transmitted analog signal is recreated from those components.

Abstract: A modem which represents the transmitted primary data stream using signal points selected via a trellis code is provided with the further capability of transmitting secondary data. In particular, a standard constellation of signal points is expanded to include a number of signal points which is greater than that needed to transmit the primary data. Particular primary data word values are representable by either of a predetermined pair of signal points associated with that value--one signal point of the pair being a standard signal point and the other being an expanded signal point. The specific one of the two signal points of the pair that is transmitted at any given time is chosen as a function of whether the value of the next bit in the secondary data stream waiting to be transmitted is a "0" or a "1".

Abstract: A modem which represents the transmitted primary data stream using signal points selected via a trellis code is provided with the further capability of transmitting secondary data. In particular, a standard constellation of signal points is expanded to include a number of signal points which is greater than that needed to transmit the primary data. Particular primary data word values are representable by either of a predetermined pair of signal points associated with that value--one signal point of the pair being a standard signal point and the other being an expanded signal point. The specific one of the two signal points of the pair that is transmitted at any given time is chosen as a function of whether the value of the next bit in the secondary data stream waiting to be transmitted is a "0" or "1".

Abstract: An apparatus monitors the convergence of the equalization training sequence in a multipoint communication network. Various latches record the period of the incoming sequence and the time to convergence, if any. A counter records the number of periods free of convergence, and upon the counter exceeding a threshold, the network train time is doubled. A register records the longest required time to convergence. This value is periodically compared to the network train time, and, if less, substituted therefor.

Abstract: A hybrid interface adapter is provided for interfacing a digital assembly to a standard data and control bus. The adapter includes level translating circuits for translating signal levels between the assembly and the control bus. The adapter also has a first port for connection to a bus through a standard connecter and a second port for connecting and mounting the adapter to the digital assembly.

Abstract: A selective secondary signalling encoder/decoder for multipoint data communications networks for use on transmission media such as telephone lines provides for selective signalling between a master broadcasting unit and however many slave units are in the network. The network functions by sending a standard (V-29) type modem training sequence and incorporating the address of the particular remote unit with which communication is desired in the data segment of the sequence. Compatibility is maintained with standard slave units that don't have this decoder by appending a sufficient number of marks to the address and message to allow for the standard starting value of a descrambler in the "data mode". When the segment is detected at each remote unit in the system, the address sent is compared to the address of the remote or slave unit.

Abstract: This invention discloses a demultiplexer with a first memory element for storing received data bits, a second memory element having individual cells connected to individual remote units (i.e. parallel output) and a logic unit for transferring the appropriate bits from the first to the second memory element in accordance with the received signal configuration. The enabling signal for the second memory element is derived from the demultiplex sync signal.