Digital network access server

• US 5,912,888 A
• Filed: 08/27/1997
• Issued: 06/15/1999
• Est. Priority Date: 06/09/1994
• Status: Expired due to Term

• Current Assignee: Network Gateway Solutions LLC (Acacia Research Corporation)
• Original Assignee: US Robotics Access Corp. (US Robotics Incorporated)
• Inventors: Hansen, Christopher R., Goodknight, Gregory Warren, Norrell, Andrew L., Suffern, Robert C., Walsh, Dale M., Schoo, Daniel L., Ngo, Thanh Q., Baum, Marc S., Herman, Jeffrey E., Jones, Terrel L., Balton, Donald C.
• Primary Examiner(s): Jung, Min
• Application Number:
  US08/920,543
• Time in Patent Office: 657 Days
• Field of Search: 370/401, 370/402, 370/465, 370/466, 370/352, 370/355, 379/93.01, 379/93.05, 379/93.06, 379/93.31
• US Class Current: 370/355
• CPC Class Codes: H04L 12/28 characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks] wireless communication networks H04W ; arrangements for dividing the transmission path H04W40/00
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors

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.

Claims

1. In a system comprising a multiplexed digital telephone line carrying a digital first telephone signal resulting from modulation of a first digital computer signal representing digital first data from a digital first computer, said telephone line also carrying a digital second telephone signal resulting from modulation of a second digital computer signal representing digital second data from a digital second computer, said system also comprising a network for receiving a digital first network signal comprising blocks of digital signals representing digital third data from a digital third computer and for receiving a digital second network signal comprising blocks of digital signals representing digital fourth data from a digital fourth computer, improved communication apparatus for enabling bilateral transmission of said digital data between said digital telephone line and said network, comprising in combination:

a telephone control interface responsive to said first telephone signal generating a digital first telephone bus signal representing said first data and responsive to said second telephone signal generating a digital second telephone bus signal representing said second data;

a network control interface responsive to said first network signal generating a digital first network bus signal representing said third data and responsive to said second network signal for generating a digital second network bus signal representing said fourth data;

a first modem responsive to said telephone control interface and said network control interface modulating said first network bus signal to form a digital third telephone bus signal representing said third data and demodulating said first telephone bus signal to form a digital third network bus signal representing said first data;

said first modem modulating said first network bus signal to form said digital third telephone signal representing said third data without conversion of said third data to an analog telephone signal;

a second modem responsive to said telephone control interface and said network control interface for modulating said second network bus signal to form a digital fourth telephone bus signal representing said fourth data and for demodulating said second telephone bus signal to form a digital fourth network bus signal representing said second data;

said second modem modulating said second network bus signal to form said digital fourth telephone bus signal representing said fourth data without conversion of said fourth data to an analog telephone signal;

a telephone bus responsive to said telephone control interface for transmitting said first and third telephone bus signals between said telephone control interface and said first modem and for transmitting said second and fourth telephone bus signal between said telephone control interface and said second modem; and

a network parallel bus responsive to said network control interface transmitting said first and third network bus signal between said network control interface and said first modem and transmitting said second and fourth network bus signals between said network control interface and said second modem;

whereby said first and third computers bilaterally communicate via said telephone line while said second and fourth computers bilaterally communicate via said telephone line.

2. An all-digital network access server connecting remote computers generating digital data to a network computer on a local or wide area network via a digital telephone line, comprising:

a plurality of modems comprising at least a first modem;

a telephone control interface receiving a plurality of multiplexed incoming calls on said digital telephone line and demultiplexing said plurality of incoming calls into time-spaced digital telephone bus signals representing said digital data from said remote computers;

a telephone bus connected to said telephone control interface transmitting said time-spaced digital telephone bus signals from said telephone control interface to said modems, including said first modem;

a digital signal processor system in said first modem demodulating said time-spaced digital telephone bus signals into incoming binary data, without conversion of said data to analog form;

a parallel bus connected to said digital signal processing system; and

a network gateway controller coupled to said modem by said parallel bus and receiving said incoming binary data from said first modem on said parallel bus, said network gateway controller placing said incoming data in a format compatible with said local area network for transmission on said local area network to said network computer.

3. The network access server of claim 2, wherein said network gateway controller further comprises a protocol manager placing said incoming binary data into a format compatible with said local area network and an interface operatively connected to said local area network and responsive to said protocol manager for placing said incoming binary data onto said local area network.

4. The network access server of claim 2, wherein said network gateway controller receives packets of data from said network computer destined for said remote computers via said digital telephone line, and places data on said parallel bus representing said data from said network computer for transmission to said first modem;

and wherein said first modem modulates said data from said network computer into second digital telephone bus signals representing said data from said network computer, without conversion of said data from said network computer into analog form.

5. The network access server of claim 4, wherein said telephone bus delivers said second digital telephone bus signals to said telephone control interface for placement on said digital telephone line for transmission to a remote computer.

6. An all-digital network access server for receiving and transmitting calls representing digital data between a multiplexed digital telephone line and a computer network having at least one computer in communication therewith, comprising:

a time division multiplexed bus organized into a plurality of time slots;

a plurality of modems, each of said modems coupled to said time division multiplexed bus;

a network interface for receiving packets of said digital data from said network and for transmitting packets of said digital data onto said network;

a parallel bus coupling said modems to said network interface;

a telephone line interface module coupling time slots of said digital telephone line to said time slots on said time division multiplexed bus; and

a plurality of processors associated with said plurality of modems for modulating and demodulating calls between said telephone line and said at network without conversion of said digital data to analog form, whereby the efficiency of transmission of said digital data between said telephone line and said at network may be improved.

7. The all-digital network access server of claim 6, wherein the bandwith of said parallel bus is available to each of said modems in said plurality of modems.