Abstract: A dynamic and automatic method and apparatus for changing the bandwidth of a digital communication session is disclosed. The communication session uses a plurality of channels for transmitting digital data between a first location and a second location. The rate of data or non-data characters in the transmitting digital data stream is detected. A utilization parameter is calculated by dividing the non-data rate by the overall transmission data rate. The number of the plurality channels is changed to maintain the utilization parameter in response to changes in the data rate.

Abstract: An apparatus and a method for use in a digital communication session is disclosed. The apparatus communicates with a like apparatus at a remote location through a digital communication network over a plurality of channels. The apparatus can change dynamically the bandwidth of the communication session by changing the number of channels utilized during the communication session. In addition, the apparatus provides a novel phase correction circuitry for reordering the digital data received from the plurality of channels to reconstitute the single transmitting digital data stream.

Abstract: A method and apparatus for allowing ISDN devices to communicate over an analog telephone line is shown. A first interface (12) accepts ISDN formatted data from an ISDN terminal equipment (TE) device (10), removes the D channel data from the ISDN data, and provides the D channel data to a synchronous modem (14). The modem (14) places onto an analog telephone line (15) a modulated carrier corresponding to the D channel data. The modulated carrier is passed through a telephone switch (16)onto another analog telephone line (17). A second synchronous modem (20) accepts the modulated carrier, demodulates the modulated carrier to recover the data, and provides the data to a second interface (22). The second interface (22) accepts the data from the modem (20), inserts the data into the D channel information in ISDN data stream, and provides the ISDN data stream to an ISDN network termination (NT) device or ISDN switch (24).

Abstract: An improved modem is described which can selectably operate in a synchronous communications mode, an asynchronous data mode, and an asynchronous command mode. A processor 47 controls the operation of the modem, adds starting and ending flags and frame check sequences to transmitted data, searches for flags and sync characters in received data, adds and deletes start, stop and parity bits required for communications with the asynchronous communications element 18, and performs zero bit insertion and deletion for HDLC/SDLC communications. Processor 47 also controls and monitors the operating parameters of the modem engine 60.