3com Corporation

George Kwan

Burton B Lo

Scott William Mitchell

Anthony Liem Pan

Marwan A Fawal

Ngo Thanh Ho

Tan Thanh Ho

Andrew Nakao

Maria B Hu

An integrated circuit is provided to convert an analog telephone signal into a digital format. The integrated circuit includes an analog-digital converter coupled to an averager. Sampled analog values are averaged at intervals and compared to a threshold level to determine a digital value.

Telephone network signal conversion system

A circuit and method thereof for arbitrating between a plurality of power sources connected to a computer system peripheral device. The circuit includes a first circuit subassembly coupled to a first power source and a second power source. The first circuit subassembly conducts current from the first power source when power is not available from the second power source, and otherwise conducts current from the second power source. The circuit also includes a second circuit subassembly coupled between the first circuit subassembly and a third power source. The second circuit subassembly conducts current from the third power source when the third power source is available and otherwise conducts current from the first circuit subassembly. The second circuit subassembly comprises a first component, a second component and a third component. The first component is coupled to the third power source and the first circuit subassembly. The first component conducts current from the first circuit subassembly when power is not available from the third power source and otherwise substantially does not conduct current. The second component is coupled to the third power source and the first component. The second component conducts current from the first component when power is available from the third power source and otherwise substantially does not conduct current. The third component is coupled to the first component, the second component and the third power source. The third component conducts current from the third power source when power is available from the third power source.

Power management for a peripheral component interconnect environment with auxiliary power

A system for reducing electromagnetic interference emissions is described. The system can include a network interface card with an Ethernet controller circuit. The Ethernet controller circuit generates an Ethernet output signal that includes a pre-emphasis component and a data component. The Ethernet controller circuit monitors the Ethernet output signal and adjusts the levels of the pre-emphasis component and the data component to reduce the electromagnetic interference caused by the network interface card but still fit the requirements for valid Ethernet signals.

System and method to reduce electromagnetic interference emissions in a network interface

A circuit and method thereof for indicating availability of a power source other than a first power source in a computer system peripheral device (such as a network adapter) connected to a plurality of power sources including. The circuit includes a circuit subassembly coupled to the first power source and a second power source. The circuit subassembly conducts current from the first power source when power is not available from the second power source and otherwise conducts current from the second power source. A first component is coupled to the circuit subassembly and conducts current when the second power source is available; otherwise, it does not conduct current. A second component is coupled to the circuit subassembly and to the first component. The second component conducts current when the first component is conducting current and otherwise does not conduct current. An output lead is coupled to the second component, and the output lead provides a signal indicating the second power source is available.

Sensing auxiliary power in various peripheral component interconnect environments

A system for reducing electromagnetic interference emissions is described. The system can include a network interface card with an Ethernet controller circuit. The Ethernet controller circuit uses a pair of programmable digital to analog converters to generate an Ethernet output signal that includes a pre-emphasis component and a data component. The Ethernet controller circuit monitors the Ethernet output signal and adjust the levels of the pre-emphasis component and the data component by adjusting the values to the digital to analog converters. By making these adjustments, the system reduces the electromagnetic interference caused by the network interface card but maintains valid Ethernet signals.

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Sunnyvale, CA, United States of America

George Kwan