Abstract: The compression method utilizes a combination of both lossy and lossless compression to achieve significant compression while retaining very high subjective quality of the reconstructed or decompressed signal. Methods and apparatus for compression and decompression of digital audio data are provided. In one preferred embodiment, the compression method or apparatus employs an approximation of a psychoacoustic model for wavelet packet decomposition and has a bit rate control feedback loop particularly well suited to matching the output bit rate of the data compressor to the bandwidth capacity of a communication channel.

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: An electrical connector particularly adapted for use in a PCMCIA standard connector designed for increased performance, ease of manufacturing, and allowing the connector casing to contain a printed circuit board having larger components is presented. A grounding shield with a hallowed-out area is implemented in the connector casing to create more room for a PC board given the same amount of vertical clearance allowing componentry to be larger than would otherwise be possible. Further, the grounding shield has a soldering cup to allow better adhesion of the solder to the plated grounding shield and to allow the connector to be more easily manufactured. The buttons used to disengage the connector from its receptacle are extended outward from the connection to provide easier accessibility in limited space circumstances. Additionally, the casing and buttons have opposing angles in order to provide more convenient and sure grasping by the user.

Abstract: A bi-directional wire-line to local area network interface, used between a remote host on a local area network (LAN), and a wire-line carrier system. A LAN media access control and physical interface converts outgoing LAN data from a LAN to an outgoing-data packet with a machine readable format. A LAN transmission control protocol and internet protocol stack identifies a protocol type of the outgoing-data packet from the LAN-MAC and physical interface. When the outgoing-data packet does not have a modem control command, a protocol converter correlates the outgoing-data packet to a channel number and depacketizes the outgoing-data packet into outgoing-binary data. Using the channel number, a connection controller and signal transform polls the outgoing-binary data and transforms the outgoing-binary data to a digitized representation of an analog signal having pulse code modulation (PCM).

Abstract: A novel line-current protection circuit and method that is useable with a PCMCIA modem card is disclosed. The protection circuit is adapted to detect when an excessive voltage is present across the tip and the ring leads of a telephone subscriber loop by sensing the amount of line-current being supplied to line interface circuitry disposed on the PCMCIA modem card. The protection circuit includes a current sensing circuit portion that is placed in series with the tip lead and which detects when the line current exceeds a predetermined maximum amount. In the event the line current exceeds the maximum, the current sensing circuit asserts an excessive line current signal. A control and delay circuit causes the relay circuit to open the electrical connection between the modem and the telephone line only when the line current exceeds a predetermined maximum amount for a minimum amount of time.

Abstract: A method for efficiently setting up a data transmission session over a communication channel between a local endpoint application and a network endpoint application with a proxy engine in a manner that is transparent to the user. The proxy engine is placed in simultaneous communication sessions with the local endpoint application and the network endpoint application. The proxy engine determines the network control protocols that are supported by both the network endpoint application and the local endpoint application. The proxy engine enables the network control protocols that are supported by both the network endpoint application and the local endpoint application. Optionally, the proxy engine enables data compression techniques that are supported by both the network endpoint application and the proxy engine.

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.

Abstract: A method for coordinating and controlling multiple data streams representing a data transmission session that terminate in different termination units (such as network access servers). The data streams are transmitted over two or more links, collectively forming a "bundle". The termination units are linked together preferably over a local area network. One of the termination units that receives a data stream is designated as the termination unit to receive and reconstruct the call. The designated termination unit is the "owner" of the bundle. The termination unit broadcasts an advertisement consisting of a bundle mapping update packet software structure with an identification header to alert the other termination units that it is to reconstruct the call. The identification header in the advertisement notifies the other termination units that if they should receive a portion of the data stream in the bundle, they should forward their packets of data to the designated termination unit.

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 method for efficiently setting up a data transmission session over a communication channel between a local endpoint application and a network endpoint application with a proxy engine in a manner that is transparent to the user. The proxy engine is placed in simultaneous communication sessions with the local endpoint application and the network endpoint application. The proxy engine determines the network control protocols that are supported by both the network endpoint application and the local endpoint application. The proxy engine enables the network control protocols that are supported by both the network endpoint application and the local endpoint application. Optionally, the proxy engine enables data compression techniques that are supported by both the network endpoint application and the proxy engine.

Abstract: An electrical power management system for supplying power to a computer peripheral having a relatively high intermittent power demand, such as a packet-switched data radio. A first self-contained rechargeable power supply, outputting power appropriate for the electrical appliance, stores electrical energy and supplies power to the appliance. A second self-contained rechargeable power supply stores electrical energy and supplies electrical power to intermittently recharge the first power supply. The first and the second power supplies can be such self-contained units as single or multicell batteries or capacitors. Preferably, the first power supply is a battery or a capacitor and the second power source is an internal power supply of a portable personal computer.

Abstract: A reconfigurable communication interface system is provided comprising a reconfigurable communication interface device and a communication adapter cable. The reconfigurable communication interface device contains means to identify a valid communication adapter cable. After an attached communication adapter cable is recognized as valid, operational values are downloaded from outside the communication interface device and the communication interface device software is reconfigured. Operational values may be loaded from the communication adapter cable or from the host computer. Adapter cables for a wide variety of applications such as various telephone networks, various cellular telephones, Ethernet networks, PBX type networks, ISDN type networks, optical networks, or other LAN and WAN type networks are provided.

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.

Abstract: An electrical power management system for supplying power to a computer peripheral having a relatively high intermittent power demand, such as a packet-switched data radio. A first self-contained rechargeable power supply, outputting power appropriate for the electrical appliance, stores electrical energy and supplies power to the appliance. A second self-contained rechargeable power supply stores electrical energy and supplies electrical power to intermittently recharge the first power supply. The first and the second power supplies can be such self-contained units as single or multicell batteries or capacitors. Preferably, the first power supply is a battery or a capacitor and the second power source is an internal power supply of a portable personal computer.

Abstract: A method and apparatus for processing convolution coded data. The method and apparatus have lower computational requirements, while still reducing or eliminating errors caused by noise or distortion. A path metric value associated with each decoder state is updated upon the receipt of each incoming signal value. The path metric value is formed by: (1) identifying those permissible transition(s) to that decoder state that are represented by symbols having the minimum branch metric compared to the received signal value; (2) identifying those permissible transition(s) to that decoder state that originate from states with the minimum previously-computed path metric value; and (3) comparing the transitions identified in the first and second steps. From this comparison, the identity of the transition with the lowest path metric value is derived. Thereafter, the path metric chosen is stored for that given state.

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 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 for allowing data communication equipment, such as a facsimile modem, to communicate in a more reliable manner with a facsimile machine. The data communication equipment is interconnected to data terminal equipment, such as a personal computer. The data terminal equipment may include an interrupt driver or controller that only periodically directs the data terminal equipment to retrieve message data from memory and forward it, via a serial port, to the data communication equipment. If the interruption in the transmission of characters to the data communication equipment is too long, no data may be sent to the facsimile machine, which may interpret the absence of data as an indication that the communication link has been disconnected and, thus, abort the call. The method includes the steps of monitoring the message data sent to the data communication equipment for an end of line sequence.