Abstract: An interface between a computer and a telephone line includes an interface device controlled by a set of commands. The commands are divided into a plurality of categories, each of which corresponds to a class of operations performed by the interface device, with each command being included within a single category. The interface device reads a command selected from a category of commands and performs an operation from the class operations that corresponds the selected category of commands.

Abstract: An application programming interface provides for command and data communication between a user, application or driver and a telephone data processing system which provides communication between a host computer and a telephone line. The telephone data processing system is capable of processing ISDN telephone calls as well as voice or analog-originated telephone calls. The application programming interface of the invention includes a host interface, an ISDN interface and a modem interface. The host interface receives commands and data from the user. The modem interface and ISDN interface provide commands and data communication between the host interface and the appropriate telephone call processing based on telephone call type. At the top level, the specific call type processing is transparent to the user. That is, the user need not know the type of telephone call, i.e., modem or ISDN, being processed.

Abstract: An apparatus for processing telephone calls is connected between a primary rate ISDN (PRI) telephone line and a host computer. Telephone call data is transferred between the host computer and remote analog, basic rate ISDN (BRI) and/or PRI remote sites. The apparatus includes a digital signal processor that can run multiple signal processing sessions simultaneously and a control processor that can run multiple control processing sessions simultaneously. The apparatus can therefore process multiple telephone calls of one or more types simultaneously.

Abstract: An interface for connecting data-terminal-equipment (DTE) to a range of data-communication-equipment (DCE) using a multiplicity of interface standards is provided. The interface includes a DTE panel connector and a plurality of line drivers and receivers and associated electronics to select predetermined ones of the plurality of receivers and drivers for use by the DTE when cables having a predetermined configuration, corresponding to the supported interface standards, are attached. The cables connect the appropriate drivers and receivers of the DTE with the corresponding receivers and drivers, respectively, of the DCE. Additionally the cables also contain termination devices and a selection mechanism to select which drivers and receivers are to be used by the DTE to communicate with the receivers and drivers, respectively, being used by the DCE.

Abstract: A zone filtering method and apparatus, finding particular utility in an AppleTalk (trademark of Apple Computing, Inc.) internetwork, is disclosed. A network manager is able to hide zones and respective Network Visible Entities (NVE's) from nodes (routers and workstations) on branches of the AppleTalk internetwork through the use of zone filters. These nodes are thus unable to initiate communication with NVE's within the hidden zones. A zone filter is a list of zone names and an indication of whether access to the listed zones is permitted or denied. The port to which a zone filter is attached identifies which branch of the AppleTalk internetwork the zone filter applies to. A router according to the invention is capable of recognizing specific datagrams to which the zone filter is applied.

Abstract: An interface for connecting data-terminal-equipment (DTE) to a range of data-communication-equipment (DCE) using a multiplicity of interface standards is provided. The interface includes a DTE panel connector and a plurality of line drivers and receivers and associated electronics to select predetermined ones of the plurality of receivers and drivers for use the DTE when cables having a predetermined configuration, corresponding to the supported interface standards, are attached. The cables connect the appropriate drivers and receivers of the DTE with the corresponding receivers and drivers, respectively, of the DCE. Additionally the cables also contain termination devices and a selection mechanism to select which drivers and receivers are to be used by the DTE to communicate with the receivers and drivers respectively, being used by the DCE.

Abstract: A method of correcting for the impairments of phase jitter and frequency offset imposed by a transmission medium and of a clock frequency difference between a transmitting and a receiving multicarrier modem is disclosed. The method comprises two modes: a training mode that uses pilot tones, and a data mode that uses random data modulated onto many carriers. During the training mode the frequencies of the phase jitter are estimated, and the parameters of a correcting signal are initialized; during the data mode the correcting signal is used to compensate for the impairments, and then is updated from an estimate of the phase error.

Abstract: A method of correcting for the impairments of phase jitter and frequency offset imposed by a transmission medium and of a clock frequency difference between a transmitting and a receiving multicarrier modem is disclosed. The method comprises two modes: a training mode that uses pilot tones, and a data mode that uses random data modulated onto many carriers. During the training mode the frequencies of the phase jitter are estimated, and the parameters of a correcting signal are initialized; during the data mode the correcting signal is used to compensate for the impairments, and then is updated from an estimate of the phase error.

Abstract: A high-speed modem that transmits and receives digital data on an ensemble of carrier frequencies spanning the usable band of a dial-up telephone line. The modem includes a system for variably allocating data and power among the carriers to compensate for equivalent noise and to maximize the data rate. Additionally, systems for eliminating the need for an equalization network, for adaptively allocating control of a channel, and for tracking variations in line parameters are disclosed.

Abstract: A multi-channel trellis encoder/decoder is disclosed for use with multi-channel data transmission systems. For each data transmission symbol interval, trellis encoding is applied across all available channels, and for each data reception symbol interval trellis decoding is applied across all available channels. In comparision with systems employing independent trellis encoding along each available channel, the present invention reduces data throughput delays by roughly an order of magnitude, and reduces implementation complexity by roughly a factor equal to the number of transmission channels. Further, the multi-channel trellis encoder will permit different data transmission rates as well as permitting variations in signal power and/or noise power from channel to channel.

Abstract: A high-speed modem that transmits and receives digital data on an ensemble of carrier frequencies spanning the usable band of a dial-up telephone line. The modem includes a system for variably allocating data and power among the carriers to compensate for equivalent noise and to maximize the data rate. Additionally, systems for eliminating the need for an equalization network, for adaptively allocating control of a channel, and the tracking variations in line parameters are disclosed.

Abstract: The present invention relates to an apparatus and method for the simultaneous transmission of analog speech and modulated data, such apparatus and method being optimized for use over impaired and bandwidth restricted analog channels, or digital representations of such channels. In each instance of use, an evaluation is made of the available channel bandwidth, with a frequency division multiplex scheme allocating a voice sub-band, with data transmission allocated to sub-bands above, below, or around, this selected voice sub-band. The speech and data sub-band allocations are made by the multiplexor in response to user input of either a requested speech quality, a requested data rate, or a value indicating the relative user weighting of speech quality and data rate.

Abstract: A high-speed modem that transmits and receives digital data on an ensemble of carrier frequencies spanning the usable band of a dial-up telephone line. The modem includes a system for variably allocating data and power amount the carriers to compensate for equivalent noise and to maximize the data rate. Additionally, systems for eliminating the need for an equalization network, for adaptively allocating control of a channel, and for tracking variations in line parameters are disclosed.

Abstract: A high-speed modem that transmits and receives digital data on an ensemble of carrier frequencies spanning the usable band of a dial-up telephone line. The modem includes a system for variably allocating data and power among the carriers to compensate for equivalent noise and to maximize the data rate. Additionally, systems for eliminating the need for an equalization network, for adaptively allocating control of a channel, and for tracking variations in line parameters are disclosed.

Abstract: A high speed digital data modem particularly suited for use on a dial up telephone line is disclosed. For the transmit ensemble, the telephone passband is divided into sixty-four sub-bands each with a carrier located approximately in the center of each sub-band. Each carrier is amplitude and phase modulated in order to encode five (5) bits. One carrier is used as a reference signal for phase and amplitude. The modulated carriers can be changed in data content every epoch. By use of packetization of data, individual amplitude correction, and individual phase correction for each carrier, the high speed modem may achieve up to 12000 bps over a dial up line with a simultaneous 300 bps reverse channel.