3com Corporation

Curtis Tengan

Rick D Giles

Methods and apparatus for providing temperature compensation for a communications card, such as a modem or network card, to minimize retrain sequences between the communications card and another communications card during periods of temperature build-up within the communications card are disclosed. It is a feature of the invention to provide this temperature compensation regardless of the speed or temperature of arriving at a steady state temperature and regardless of the make of the communications card, host computer or computing temperature environment under examination. In a preferred embodiment, a keyword between the communications card and a host computer is compared to provide unique heat compensation for these two devices that have generally different, but consistent, heating characteristics. If the keywords do not match, a plurality of original delta values are developed in accordance with the heating characteristics between the communications card and the host computer for adjusting filter coefficients of a DSP in the communications card. Whereas, if the keywords match, a set of initial delta values having previously been developed are set. A temperature is monitored within the communications card so that whenever the monitored temperature exceeds a preselected threshold, the filter coefficients are adjusted by a delta value. The delta value corresponds to a preselected temperature range and is stored in a fast storage device to minimize the time required to alter the coefficients from one temperature range to the next. This minimizes the retraining sequences between the communications card and the another communications card. Ultimately, net character transmission throughput between the communications cards is improved and faster communications result. In one embodiment, heat or temperature is sensed by a thermistor and provided to the DSP for retrieval of the delta values from a fast storage device whenever the ambient temperature within the communications card exceeds some temperature threshold.

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Bountiful, UT, United States of America

Curtis Tengan