Patent ID: 7973538
Filing Date: 2011-07-05
Classification: G01R,H04L

Abstract:
1. Apparatus, comprising: power circuitry connectible to a multi-conductor cable, the power circuitry being operative to transfer electrical power from a power-sourcing equipment (PSE) to a powered device (PD) over the multi-conductor cable; and hazard detection circuitry connectible to the multi-conductor cable, the hazard detection circuitry being operative to sense an electrical characteristic of the multi-conductor cable and generate a detection signal indicating whether a potentially hazardous abnormal operating condition exists in the multi-conductor cable based on the sensed electrical characteristic, wherein: the PSE is one of a plurality of PSEs operative to generate respective output power signals at respective powered communications interfaces, the output power signals including respective output voltages; the multi-conductor cable is one of one or more multi-conductor cables connecting the powered communications interfaces of the PSEs to a powered communications interface of the PD, the cables including at least two distinct sets of conductors, each set of conductors carrying a respective one of the output power signals; and the hazard detection circuitry comprises short-circuit detection circuitry coupled to the cables, the short-circuit detection circuitry being operative to detect the presence of a hazard-producing short-circuit connection between the sets of conductors, the hazard-producing short-circuit connection causing additive combining of the output voltages of the PSEs to generate a combined voltage at the PD greater than each of the output voltages of the PSEs.