Com21, Inc.

Kenneth Gorman

Ali Raissinia

Mark E Laubach

Paul Baran

Sanford L Helton

A two-way hybrid fiber-coax cable networks offering high-speed broadband communications delivered via a cable modem service. Bi-directional transmissions of packets between the head-end controller (Cable Modem Terminal System) and cable modems (subscriber terminal units) is accomplished using a cable television Media Access Control (MAC) protocol. In Hybrid Fiber-Coax (HFC) networks, the invention provides a Reverse Path Multiplexing (RPM) function permitting the coupling of a large number of return path (plant) RF ports (return ports) to be coupled to a receiver card in the CMTS. One aspect of this invention is that one or more upstream traffic schedulers reside within the CMTS equipment with the responsibility of scheduling the upstream transmissions from cable modems. The cable modems are distributed across many return ports. The data from each cable modem must be successfully received by the head-end controller without being compromised by the effects of noise funneling. The knowledge of when a cable modem will transmit is used to open an RF switch in the RPM.

Reverse path multiplexer for use in high speed data transmissions

A method for enhancing the functionalities of a subscriber terminal unit (STU) or ADSL terminal unit (ATU) through the use of different types of application interface modules (AIMs). This is accomplished by incorporating a slot in the STU/ATU through which a detachable AIM can be inserted and electrically coupled to the STU/ATU. The STU/ATU has circuitry for determining which particular type of AIM has been inserted. Depending on the type of AIM that has been inserted in the STU/ATU (e.g., installation, telephony, diagnostics, network interface, television, etc.), management information specific to the particular AIM is sent by the STU/ATU upstream to the headend unit. In response, the headend unit provides applications service(s) to the STU/ATU, depending on the particular type of device inserted into the subscriber terminal unit.

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Danville, CA, United States of America

Kenneth Gorman