Abstract: A conventional computer is coupled to an analog telephone transmission link by means of an analog/digital conversion interface adapter. Modem transmission is accomplished by performing the modulation and demodulation functions digitally in the computer's existing processor which executes programs which transfer data between the computer's memory and the interface adapter. Using the same interface adapter and existing processor, the arrangement may be used to send and receive images in the form of standard V.29 format facsimile data, to send and receive data operating as a synchronous IBM 3270 compatible terminal device, or to record and play back conventional voice transmissions rather than data to implement a telephone answering, voice message handling, and telemarketing systems.

Abstract: A method and an apparatus for encoding an image signal. The apparatus includes an acquisition module disposed to receive the image signal. A first processor is coupled to the acquisition module. At least one encoder processor is coupled to the first processor. The at least one encoder processor produces an encoded image signal under control of the first processor. The method includes the steps of converting an input image signal into a predetermined digital format and transferring the digital format image signal to at least one encoder processor. The method further includes the step of applying, at the at least one encoder processor, a hierarchical vector quantization compression algorithm to the digitized image signal. At the next step, a resultant encoded bit stream generated by the application of the algorithm is collected. The method and apparatus of the present invention may be used in conjunction with an ordinary modem to transmit and/or receive audio, video sequences or still images.

Abstract: A method and an apparatus for encoding an image signal. The apparatus includes an acquisition module disposed to receive the image signal. A first processor is coupled to the acquisition module. At least one encoder processor is coupled to the first processor. The at least one encoder processor produces an encoded image signal under control of the first processor. The method includes the steps of converting an input image signal into a predetermined digital format and transferring the digital format image signal to at least one encoder processor. The method further includes the step of applying, at the at least one encoder processor, a hierarchical vector quantization compression algorithm to the digitized image signal. At the next step, a resultant encoded bit stream generated by the application of the algorithm is collected. The method and apparatus of the present invention may be used in conjunction with an ordinary modem to transmit and/or receive audio, video sequences or still images.

Abstract: Apparatus and method for enabling bilateral transmission of digital data between a local area network and telephone company networks employing both analog and digital telephone lines. A modem modulates signals responsive to signals from a local area network representing an outgoing call to form digital telephone signals suitable for transmission by a telephone line and suitable for demodulation by receiving analog modems. A circuit switched time division multiplex bus transmits the digital telephone signals to the telephone line. The modem also demodulates incoming digital telephone signals to form digital network bus signals divided into packets. A packet bus transmits the digital network bus signals to a network interface which processes the signals and transmits them to the local area network.

Abstract: A full-duplex modem having improved transmission speeds over voice grade telephone circuits that extends the concepts of asymmetric transmission to include echo cancellation techniques. The preferred modem has a high speed forward channel and an overlapping low speed back channel and is capable of transmitting or receiving over either of the channels, depending on the relative data rates. A narrow band echo canceler substantially cancels all or part of reflected transmit signals. Because the echo cancellation technique employed is narrow band, there is a significant reduction in the complexity and computational requirements for the modem.

Abstract: A method and an apparatus for encoding an image signal. The apparatus includes an acquisition module disposed to receive the image signal. A first processor is coupled to the acquisition module. At least one encoder processor is coupled to the first processor. The at least one encoder processor produces an encoded image signal under control of the first processor. The method includes the steps of converting an input image signal into a predetermined digital format and transferring the digital format image signal to at least one encoder processor. The method further includes the step of applying, at the at least one encoder processor, a hierarchical vector quantization compression algorithm to the digitized image signal. At the next step, a resultant encoded bit stream generated by the application of the algorithm is collected. The method and apparatus of the present invention may be used in conjunction with an ordinary modem to transmit and/or receive audio, video sequences or still images.

Abstract: A method of processing incoming digital telephone calls from remotely located call originators which are destined for receipt by a host computer system. The host computer system is linked to the telephone network by a network access server. The call originators may be any type of data terminal, such as a personal computer or a credit card swipe, which is connected to a modem. The network access server extracts control signals imparted onto the telephone line and correlates the control signals with particular communications, routing or applications protocols identified with the call originators. The modem in the network access server which answers the call is configured during the call connect process and placed in a compatible format for the communications protocol of the incoming call. This dynamic custom configuration of the modem reduces the overall telephone call connection and processing time.

Abstract: A method and an apparatus for encoding an image signal. The apparatus includes an acquisition module disposed to receive the image signal. A first processor is coupled to the acquisition module. At least one encoder processor is coupled to the first processor. The at least one encoder processor produces an encoded image signal under control of the first processor. The method includes the steps of converting an input image signal into a predetermined digital format and transferring the digital format image signal to at least one encoder processor. The method further includes the step of applying, at the at least one encoder processor, a hierarchical vector quantization compression algorithm to the digitized image signal. At the next step, a resultant encoded bit stream generated by the application of the algorithm is collected. The method and apparatus of the present invention may be used in conjunction with an ordinary modem to transmit and/or receive audio, video sequences or still images.

Abstract: A method and an apparatus for encoding an image signal. The apparatus includes an acquisition module disposed to receive the image signal. A first processor is coupled to the acquisition module. At least one encoder processor is coupled to the first processor. The at least one encoder processor produces an encoded image signal under control of the first processor. The method includes the steps of converting an input image signal into a predetermined digital format and transferring the digital format image signal to at least one encoder processor. The method further includes the step of applying, at the at least one encoder processor, a hierarchical vector quantization compression algorithm to the digitized image signal. At the next step, a resultant encoded bit stream generated by the application of the algorithm is collected. The method and apparatus of the present invention may be used in conjunction with an ordinary modem to transmit and/or receive audio, video sequences or still images.

Abstract: A method in which correctable I/Q imbalance errors in a complex receiver can be detected and compensated for digitally without the use of special calibration signals. Differential D.C. offset errors are compensated by averaging the incoming I.sub.d and Q.sub.d digital signals and subtracting from them an expected value of differential D.C. offset, for example, computed from the long term average of the I and Q signals to create I' and Q' signals. Differential gain imbalance errors are corrected by calculating a root means square average of the I' and Q' digital signals and applies to them compensation coefficients K.sub.x and K.sub.y determined from either the RMS average or from a Stochastic Gradient Algorithm. The DSP compensates for the quadrature phase errors by calculating a compensation matrix which is independent of the frequency of the carrier and applies the compensation matrix to the I' and Q' digital signals.

Abstract: A conventional computer is coupled to an analog telephone transmission link by an analog/digital conversion interface adapter. Modem transmission is accomplished by performing the modulation and demodulation functions digitally in the computer's existing processor which executes programs which transfer data between the computer's memory and the interface adapter. Using the same interface adapter and existing processor, the arrangement may be used to send and receive images in the form of standard V.29 format facsimile data, to send and receive data operating as a synchronous IBM 3270 compatible terminal device, or to record and play back conventional voice transmissions rather than data to implement a telephone answering, voice message handling, and telemarketing systems.