Abstract: An apparatus (101) and method for interfacing between a processor (103) and a communications channel (105), the processor operable in data terminal equipment (102) such as a computer having a communications application program, to provide for data transmission and reception over a communications channel (105), utilizing the computer processor without additional or redundant microprocessor or digital signal processor components. The apparatus and method provide for data transfer between the interface apparatus (101) and the communications channel (105) at a first, determinate frequency corresponding to a specific data transmission rate. The apparatus and method provide for data transfer between the interface apparatus (101) and the processor (103) at a second, indeterminate frequency, and provides for interim data storage in memory (115) between data transmission (or data reception) and data processing, such as modulation and demodulation, by the computer processor (103).

Abstract: The present invention provides a device (200, 300), system (400, 500) and method for real-time streaming of a multimedia file stored in a remote server over a packet network to a multimedia client connected to the same network via a low-speed access link such as an analog telephone line. The invention operates to provide significantly improved QoS with respect to both quality and delay.

Abstract: The present method (200,300, 400) and device (500, 600, 700) modify phase two of the format set forth in the V.34 Recommendation of the International Telecommunication Union-Telecommunication Standardization Sector to prevent premature disconnection of calls between a call modem and an answer modem. The method and device efficiently ensure connection of the call for high speed data transmission over voiceband channels, by modification of one of: a phase preliminary to phase one and phase two. One implementation, in the answer modem, includes transmitting a signal having first information, followed by a Signal S comprising of aguard tone and a signal S1, wherein an energy of a predetermined guard tone is greater than an energy of a predetermined range of frequencies of the Signal S1; and continuing transmitting and receiving in accordance with the modified V.34 operation.

Abstract: A system (10) and method for simultaneously enabling a voice and a data session has a voice data modem (200) coupleable to a data port (255), a voice jack (240), and a telco jack (280). The data port (255) is connected to data terminal equipment (100), the voice jack (240) is connected to a telephone, and the telco jack (280) is connected to a telephone network (120). The data ports for each of a plurality of voice data modems are connected to other data terminal equipment (180, 181, 182), the voice jacks are connected to first extensions of a net telco jacks are connected to different, second extensions of the network. The voice data modem (200) may receive multiplexed voice and data over a single, first extension of the network through the telco jack, (280), dumultiplex and decompress the voice and data, transmit or retransmit the voice separately from the data over a second network extension via the voice jack (240), and transmit the data to data terminal equipment through a data port or interface (255).

Abstract: An automatic modulation mode selecting unit (208) and a method (100) provide for selection from a plurality of modulation modes having an optimized transmission time for a data file. This is particularly useful where a small data file is to be transmitted, such as for a hand-held message pad. The present invention may select a modulation mode having a slow data rate but a short training time to achieve a shorter transmission time a small data file in comparison with using another modulation mode having a fast data rate but a longer training time, and thus a longer transmission time. The automatic modulation mode selecting unit includes a mode select controller (202), a mode computer (204), and a mode-select switch (206) for selecting a modulation mode based on a calculated optimized transmission time.

Abstract: A two wire modem 200, 500, 600 and a method 1000, 1100 select a carrier frequency and a symbol rate from a predetermined plurality of carrier frequencies and symbol rates to communicate with another modem over a communication media in a full duplex mode based on signal and echo characteristics of the communication media estimated by the modem.

Abstract: Capability is provided to dynamically reallocate the multiplex data stream from one communication channel to a plurality of communication channels. This allows increased flexibility in responding to degradation of the main communication channel and in accommodating increased user demand exceeding the capacity of the main channel. A table is generated to control the DTE PORTs accessed during each slot of a multiplexer frame. A separate table is generated to control the allocation of multiplex data between communication channels. Both tables are generated based upon a common Hash table. A plurality of Hash tables correspond to different output data rates and permit the output rate of the multiplexer to coincide with the maximum output rate capacity of an associated transmission device such as a modem.

Abstract: A two wire modem selects a carrier frequency in a baud rate from a predetermined plurality of carrier frequencies and baud rates to communicate with another modem over a communication media in a full duplex mode based on signal and echo characteristics of the communication media estimated by the modem. In addition, the processes of estimating channel characteristics and estimating range are combined in a common start up procedure comprising a plurality of successive time segments for a call modem to communicate with an answer modem over a communication media. Still further, a method is provided for switching from a primary communication media connection to a secondary connection of a data communications network for communication by first and second modems coupled to the network. More specifically, when a failure is detected in the primary connection, the secondary connection is qualified before switching thereto.

Abstract: Automatically restoring data transmission by monitoring line degradation and switching to a new line (or lines) when line quality falls below a prescribed standard. Data transmission is maintained on the leased line while communication is being established on the dial line, so as not to disrupt data transmission; communication is established across two dial lines to restore full-duplex transmission; energy is maintained on the dial lines at times when data is not being transmitted to prevent a change of channel on a dial line; a signal processor, associated memory, and analog interface circuitry provide the data restoral functions; control of the restoral procedure is handled by one modem (e.g., the calling modem), and commands are sent to the other modem over either the leased or dial lines.

Abstract: A two wire modem selects a carrier frequency in a baud rate from a predetermined plurality of carrier frequencies and baud rates to communicate with another modem over a communication media in a full duplex mode based on signal and echo characteristics of the communication media estimated by the modem. In addition, the processes of estimating channel characteristics and estimating range are combined in a common start up procedure comprising a plurality of successive time segments for a call modem to communicate with an answer modem over a communication media. Still further, a method is provided for switching from a primary communication media connection to a secondary connection of a data communications network for communication by first and second modems coupled to the network. More specifically, when a failure is detected in the primary connection, the secondary connection is qualified before switching thereto.

Abstract: In a multipoint data communications system used with analog communications channels that may insert undesirable frequency offsets in a modem carrier frequency, a slave modem that adjusts its transmit carrier frequency compensates for the offset influenced communications channel. A central modem device does not have to train up to slightly offset frequencies when the communications channel is effectively removing the offset added by a slave modem at its transmitter site.

Abstract: An echo cancellation modem for full-duplex communication over a channel with a remote device in accordance with one of several possible modulation schemes suitable for different channel qualities, respectively. The modem includes an echo canceller for reducing echo components appearing in the channel signal while leaving a residual echo component in the echo reduced channel signal, a monitor for determining the quality of the channel based on an analysis of the residual echo component, and a controller for selecting an acceptable modulation scheme, based on the analysis of the monitor. The modem selects the acceptable modulation scheme prior to data communication and it also requests changes to the appropriate level of modulation during data communication when the monitor indicates that the channel quality has changed significantly. The modem requests the remote device to operate at the selected rate and begins operating at the selected rate only if the remove device concurs.