Patent ID: 7417443

Claim:
A method of determining an effective resistance between a power sourcing equipment and a powered device, the powered device exhibiting an interface and an operational circuitry, the method comprising: prior to connecting power to the operational circuitry of the powered device, impressing two disparate current flow levels (I 1 , I 2 ) between the power sourcing equipment and the powered device; measuring the voltage at said powered device interface (V PD1 , V PD2 ) responsive to each of said impressed disparate current levels; measuring the voltage at said power sourcing equipment (V PSE1 , V PSE2 ) responsive to each of said impressed disparate current levels; and determining the effective resistance between the power sourcing equipment and the powered device responsive to said V PD1 , V PD2 , V PSE1 , V PSE2 , I 1 and 1 2 .