Abstract: A method of controlling a power over Ethernet system, the method comprising: sequentially powering a plurality of powered devices over communication cabling; determining a first total power consumption responsive to the powering of the plurality of powered devices; in the event that the determined first total power consumption exceeds a predetermined maximum power level, disabling power from at least one of the powered plurality of powered devices thereby reducing power consumption to less than the predetermined maximum power level; responsive to the disabling power, defining a connection power limit lower than the maximum power level by a guard band; monitoring a second total power consumption subsequent to the disabling power; and enabling power to a powered device only in the event the monitored second total power consumption is less than the connection power limit.

Abstract: A method of determining impedance comprising: supplying power to a powered device from a power sourcing equipment at a first current limited level, Ilim1; measuring, at a plurality of times a voltage associated with the output of the power sourcing equipment; determining a minimum voltage, Vmin1, of the measured plurality of voltages; determining an associated time of the determined Vmin1; removing the supplied power from the powered device; subsequent to the removing, supplying power to the powered device from the power sourcing equipment at a second current limited level, Ilim2, the Ilim2 being different than the Ilim1; measuring, at the determined associated time in relation to the beginning of the supplying power at the Ilim2, a voltage associated with the output of the power sourcing equipment, Vmin2; and determining an impedance responsive to the Vmin1, Vmin2, Ilim1 and Ilim2.

Abstract: This invention discloses a local area network including a hub, a plurality of nodes, communication cabling connecting the plurality of nodes to the hub for providing data communication, and a power supply distributor operative to provide at least some operating power to at least some of the plurality of nodes via the communication cabling.

Abstract: A method for rapidly reducing power in the event of a change in power source conditions, comprising: obtaining an indicator of one of current power consumption of ports being supplied power and current power allocation of ports being supplied power; storing for at least one possible power source condition different than a current power source condition identifiers of ports being supplied power for which power is to be reduced, the identifiers being associated with the at least one power source condition; and in the event of a change in power source condition from the current power source condition to a revised power source condition; identifying the revised power source condition as one of the at least one power source condition; and reducing power to ports in accordance with the stored identifiers associated with the revised power source condition.

Abstract: A power supply subsystem for providing electrical power to a local area network node over communication cabling, the power supply subsystem containing: a power management and control unit; programmable current limiting circuitry responsive to the power management and control unit to provide a programmable current limited output; voltage measurement means; and at least one of a combiner and a power supply interface operative to couple the programmable current limited output to the communication cabling. The power management and control unit is operative to: measure, utilizing the voltage measuring means at a plurality of pre-determined intervals, a voltage developed in accordance with the coupled programmable current limited output; and determine, as a consequence of the measured voltage whether characteristics of the node allow it to receive power over the communication cabling.

Abstract: Power sourcing equipment providing a plurality of power sources for connection over communication cabling to a single powered device, the power sourcing equipment comprising: a first power source; a second power source; a control circuit; a current sensor adapted to monitor an output current of the first power source, the current sensor being operatively connected to the control circuit; and a voltage regulating means associated with one of the first power source and the second power source, the voltage regulating means being responsive to the control circuit, the control circuit being operative responsive to the monitored output current to operate the voltage regulating means so as to maintain the monitored output current within a pre-determined range.