Adtran Gmbh

Universal Data Systems, Inc.

Thomas L Ballard, Iii

John B Wilkes, Jr

Kevin W Schneider

W Stuart Venters

Michael Scott Sansom

Philip David Williams

Robert Barrett

Gary M Willoughby

Jon Thomas Zakrzewski

Mark Jeffries Ogden

Kathy L Cunningham

William B Waldron, Jr

Relatively low cost asymmetric digital subscriber line (ADSL) service and auxiliary POTS service are delivered over extended distances (e.g., at least 20&#x2013;25 kft), by a hybrid ADSL-SDSL architecture insertable between central office and remote sites of an ADSL system. Central office and remote site transceivers employ trellis coded pulse amplitude modulation and a data rate that conforms with the signal transport capability of an extended distance symmetric DSL (SDSL) loop, while providing a 64K POTS channel. The central office and remote site transceivers controllably insert idle asynchronous transfer mode (ATM) cells in upstream and downstream ADSL channels to compensate for timing differences with ADSL equipment.

System for providing extended range ADSL service with auxiliary pots channel over single-line digital subscriber link

An upstream transceiver, coupled to an upstream end of a long haul, single digital subscriber loop of an extended range asymmetrical digital subscriber line communication system, 'spoofs' a (co-located) digital subscriber line access multiplexer to reduce its downstream data rate over a short haul loop to the upstream transceiver. The reduced downstream data rate is compatible with the data rate that can be supported by the long haul loop and also accommodates an auxiliary (64K) POTS channel thereover. The reduced data rate may be derived by preliminary signal quality measurements upon the long communication loop conducted between the upstream transceiver and a downstream transceiver coupled to a remote end of the long haul loop.

Method of inducing ADSL communication device to transmit at downstream signaling rate optimized for extended range ADSL service with auxiliary pots channel over SDSL link

An autobaud mechanism is executed by transceivers coupled to opposite ends of a communication loop, such as an extended range SDSL loop, to resolve the maximum data rate that can be supported by the loop, using signal power and quality measurements to first estimate the length of the SDSL loop and thereafter iteratively adjust baud rate and/or number of bits/per baud, as necessary, to realize an SDSL baud rate that will ensure error-free transmission over the loop.

Method of establishing signaling rate for single-line digital subscriber link providing extended range ADSL service with auxiliary pots channel

A secure modem (151) sequence detector (101) may be programmed to detect the presence of various predetermined sequences in a bit stream (103). When detecting an escape ('ESC') sequence, the detector performs a fast pre-qualifying test to detect the presence of an ESC sequence. When an ESC sequence is detected, a second validation/placement routine is executed which validates the ESC sequence, and determines the bit position in the ESC sequence where the ESC sequence was detected. The second routine requires only a half-ESC sequence search for validation and placement. The detector may also be programmed to detect a start of message ('SOM') sequence.

Sequence detection method

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Madison, AL, United States of America

Thomas L Ballard, Iii