3com Corporation

U.S. Robotics Corporation

U.S. Robotics Access Corp.

Utstarcom, Incorporated

3 Com Corporation

Robert C Suffern

Andrew L Norrell

Marc S Baum

Donald C Balton

Daniel L Schoo

Terrel L Jones

Dale M Walsh

Christopher R Hansen

Thanh Q Ngo

Lih-Shyng Tzeng

Gregory Warren Goodknight

Peter P Jankus

Jeffrey E Herman

Khodor S Elnashar

Clifford H Wallach

Ronald Joseph Sullivan

Brett Walter Chaveriat

Jeffery E Herman

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.

Host computer digital signal processing system for communicating over voice-grade telephone channels

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.

Network access method and network access server therefor

Host computer digital signal processing system for communicating over

Digital network access server

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. The control signals may also be used by network access server for customized call routing or by the network access server or host computer system to run specialized application programs. The method is particularly suitable for use by large enterprises handling a high volume of incoming calls in which data is transmitted to the host computer system according to a variety of different communications protocols, or where the implementation of different routing paths or applications programs is desireable according to the identity or classification of the call originator.

Telephone call routing and switching techniques for data communications

A processor on an add-on card that arbitrates demand on a memory unit on the add-on card. The processor and memory unit are used for the underlying functionality of the add-on card. The processor determines an appropriate time to allow interface operations to the memory unit when the memory unit is not already being accessed for the underlying functionality of the card. By using the processor and memory unit on the add-on card for interface operations to the host computer, the add-on interface circuitry on the add-on card can be minimized and simplified.

System for arbitrating demand on memory during configuration of a

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. The control signals may also be used by network access server for customized call routing or by the network access server or host computer system to run specialized application programs. The method is particularly suitable for use by large enterprises handling a high volume of incoming calls in which data is transmitted to the host computer system according to a variety of different communications protocols, or where the implementation of different routing paths or applications programs is desirable according to the identity or classification of the call originator.

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.

Modem input/output signal processing techniques

A modem for connecting data terminal equipment (DTE) to a remote DTE via a general switched telephone network or leased lines at data rates of 300, 1200 and 2400 bps using standard modulation techniques, and additonally providing virtual full duplex transmission capability at 9600 bps using trellis code modulation (TCM). The high-speed 9600 bps path is implemented by asymmetrical frequency division of the available bandwidth into a high speed, wideband forward channel (9600 bps) and a low speed, narrowband backchannel (300 bps). The high speed transmitting channel is assigned to that modem having the greatest data demand and the direction is dynamically reversed whenever the amount of data awaiting transmission over the low speed channel exceeds a predetermined maximum backlog, provided that a direction reversal has not taken place for at least a specified minimum interval during which use of the forward channel is guaranteed. To improve the efficiency of the backchannel, extended data formats are added to the MNP link protocol for use in backchannel transmission and to control direction reversals on the line. The modem is implemented with three available general purpose microprocessors with interprocessor communications being synchronized by a timer driven interrupt mechanism. A hardware timer/counter built into one of these processors is used to monitor the signals on the telephone line to detect and distinguish answer tones, voice signals, busy signals, ringback signals and dial tones. A hardware counter/timer is also used to measure the width of the start bit from the serial port to form the basis for a calculation of the baud rate being used by the DTE.

Asymmetrical duplex error-controlled modem

Growing community of inventors

Chicago, IL, United States of America

Robert C Suffern