Abstract: A sketching system sketches first notes to be transmitted over a telephone line and receives second notes from another sketching system. The sketching system includes a signal de-combiner device, receiving the second notes from the another sketching system and voice data as a combined signal via the telephone line and de-combining the combined signal into the second notes and the voice data. In addition, the sketching system includes a sketching unit connected to the signal de-combiner. The sketching unit includes a note displaying device displaying the first and second notes, a note generating device generating the first notes, and a processor connected to the note displaying and generating devices and to the signal de-combiner, receiving the first notes from the note generating device, receiving the second notes from the de-combiner, and transmitting the first and second notes to the note displaying device.

Abstract: A simultaneous voice and data modem coordinates the storage of voice messages and data messages on an audio answering machine and a personal computer, respectively. This allows the called party to subsequently retrieve, via the simultaneous voice and data modem, both a voice message and an associated data message, i.e., a multimedia message, where the called party listens to the voice message while viewing the data message. The called party can retrieve the multimedia message either locally or from a remote location.

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: Digital data is encoded using a modulus m converter to produce fractionally encoded words, where m is the nearest integer larger than 2.sup.c and c is a noninteger. The fractionally encoded words are mapped into a symbol constellation having m symbols to produce a two dimensional data signal. The data signal is added to a two dimensional analog signal, which was obtained by encoding an input analog signal, to produce a combined two dimensional signal. The combined signal is modulated using QAM and then transmitted over a communication channel.

Abstract: In a simultaneous voice and data communications system comprising two modems, an autorate feature is implemented in one illustrative method by adding a silence detector to the receiver circuitry of at least one of the modems in such a way that noise statistics for the communications channel are only accumulated during intervals of silence. If the resulting noise statistics exceed a predetermined threshold, i.e., the communications channel is too noisy, the receiving modem negotiates a lower data rate with the transmitting modem. In another illustrative method, the transmitting modem provides a signal, which represents an interval of silence, to the receiving modem. Upon receipt of the signal, the receiving modem accumulates error statistics in order to determine if the communications channel is too noisy.

Abstract: A method and apparatus for 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 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. Both half-duplex and full-duplex operation is available in accordance with the disclosure.

Abstract: An arrangement for modulating orthogonal signals with an analog signal or a digital information signal. In either event, the information signal is partitioned into component signals which respectively modulate an associated one of the orthogonal signals. The analog signal has a predetermined bandwidth and may be represented by samples generated at no less than a predetermined rate. The component signals derived from this analog signal, on the other hand, may be represented by samples generated at a rate which is less than the predetermined rate. Apparatus is incorporated which detects a predetermined event which, in turn, determines whether the orthogonal signals are modulated by the analog or digital information signal. The value of the latter signal may be known at any time, such as when the digital information signal is a training sequence, or may be unknown. The foregoing modulation arrangement can also incorporate privacy or encryption schemes.

Abstract: In a simultaneous voice and data communications system, a voice signal is added to a data signal before transmission over the public switched telephone network (PSTN). In particular, in every signaling interval, a signal point is selected for transmission as a function of both the voice signal and the data signal. Since the voice signal is effectively offset by the data signal, compandors normally found in the PSTN are not effective in improving the signal to noise ratio of the transmitted voice and data signal. Therefore, the voice signal is additionally companded in the transmitter before transmission over the PSTN. This additional companding by the transmitter improves the signal to noise ratio of the combined voice and data signal.

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 method and apparatus for control of 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. Both half-duplex and full-duplex operation is available in accordance with this invention. The illustrative embodiment includes a controller that is sensitive to input signals applied to the modem disclosed herein.

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 communications system simultaneously transmits both a primary data signal and a secondary voice signal in such a way that the dynamic range of the secondary voice signal is increased even though deliberate errors are introduced into the transmitted data portion of the signal. In particular, the communications system includes an error correcting technique like channel encoding and the constellation signal space is divided into a number of regions, where at least one of the regions overlaps with another region. The primary signal is channel encoded to select a particular one of the number of regions, the region being represented by a reference signal point value. The voice signal is encoded to provide a signal point vector, which is added to the reference signal point in such a way that the resultant signal point is located in the overlapping region thereby deliberately introducing an error into the resulting transmitted signal point stream.

Abstract: A simultaneous voice and data (SVD) modem is coupled to both a fax machine, which includes a fax modem, and a telephone set. When the fax machine initiates a fax-call, the SVD modem emulates signaling of the local loop. This allows the fax machine to operate without requiring modifications to the fax machine. After establishing a data connection with a far-end SVD modem, the near-end SVD modem demodulates the fax modulation signal from the fax machine to recover the fax data. The fax data is then re-modulated using a data modulation technique for transmission to the far-end SVD modem. The latter, demodulates the data portion of the signal to recover the fax data, which is then re-modulated using a fax modulation technique for transmission to a far-end fax machine.

Abstract: In a simultaneous voice and data communication system, a stream of signal points is partitioned into a plurality of symbol blocks, each symbol block including a data segment and a control segment. The data segment carries information from a user, i.e., user data, while the control segment provides control information. A voice signal is then added to at least a portion, or all, of the signal points of each symbol block to provide for simultaneous voice and data transmission to an opposite endpoint. The control information may represent information from a secondary data source, and/or may include information about the characteristics of the succeeding block, e.g., the user data rate, and information pertaining to characteristics of the communications channel.

Abstract: In a simultaneous voice and data communications system, a voice signal is mapped into an N-dimensional signal space constellation as a vector, and added to a reference signal point, i.e., a data symbol, where the data symbol is selected from a constellation of data symbols every signaling interval as a function of a data signal. The constellation signal space is further divided into a number of shaped regions, where each region is associated with a different one of the data symbols. The shape of each region is selected as a function of the characteristics of the voice, or audio, signal. In particular, each region illustratively has a rectangular shape.

Abstract: A method and apparatus for 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 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. Both half-duplex and full-duplex operation is available in accordance with the disclosure.

Abstract: An analog signal is added to a data signal that specifies a symbol in a symbol constellation to produce a combined signal that is transmitted to a receiver. The symbol constellation is picked from a plurality of symbol constellations having differing symbol densities based on the amplitude of the analog signal.

Abstract: In the public switched telephone network, an originating modem can identify an answering modem, e.g., as to the type of modem it is, by detection of a low-level identification signal sent from the answering modem. The low-level identification signal is hidden within an industry standard "answer tone," e.g., a CCITT V.25 answer tone of 2100 Hz. If the low-level identification signal is detected by the originating modem, the industry standard "handshaking" procedure is terminated and a non-standard handshaking procedure is implemented. If the identification signal is not detected by the originating modem, the industry standard handshaking procedure is simply completed.

Abstract: Fractional rate modulation is accomplished by separating incoming data into frames of bits. Each frame in partitioned into bit words of unequal lengths. The words are divided by a modulus to obtain remainders. The remainders are transmitted using, for example, QAM modulation. At the receiving end, the process is reversed. The ratio of baud rate of the system to the incoming bit rate defines the modulus as well as the number of QAM modulation points. A "data rate throttling" technique takes advantage of the capabilities provided by the foregoing to allow the rate at which data is channel mapped and transmitted over a communication channel to be easily varied in small increments.

Abstract: A method and system for communicating data over a communications channel such as a telephone line includes the conversion of asynchronous data transmitted from a diagnostic microcomputer through a modem into synchronous data for transmission over the communications channel. The method includes the use of error vectors to shift the asynchronous data into a continuous synchronous stream of data bits.