Importance

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Abstract

Methods and apparatus for using and/or switching to an auxiliary communication pathway to increase system reliability and/or reduce maintenance costs is disclosed. One feature is directed to a smart network interface device (SNID) implemented using latching relays. The SNID has very low power requirements and can be remotely controlled in a reliable manner through the use of simple tone signal commands over common POTS line pairs. Upon detecting a fault condition on a main line pair, the SNID is remotely instructed to disconnect the faulty line pair and switch the telephone customer's line connected to the faulty line pair to an auxiliary line pair. To operate in a POTS telephone environment without the need for an additional power supply, the SNID is designed to be powered from the power available from the auxiliary line pair. The power supply circuitry of the SNID is designed to have a near infinite input impedance with regard to input signals below twenty volts. Tone signals which are readily generated by equipment commonly found within the telephone network are used as control signals to reduce the cost associated with providing a command transmitter. Control signals of relatively long durations, e.g., in excess of 0.1 second, are used to reduce the accuracy required of the tone generation and detection equipment needed and to reduce the chance of erroneous command signals.

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First Claim