Patent ID: 8356191

Claim:
A method for determining resistive power loss through a channel between Power Sourcing Equipment (PSE) and a Powered Device (PD), the method comprising: obtaining a first voltage measurement, representing a voltage drop across the PD while a first load is applied by the PD to the channel; obtaining a first current measurement, representing current passing between the PSE and the PD while the first load is applied by the PD to the channel; obtaining a second voltage measurement, representing the voltage drop across the PD while a second load is applied by the PD to the channel in place of the first load, the second load being different than the first load; obtaining a second current measurement, representing current passing between the PSE and the PD while the second load is applied by the PD to the channel in place of the first load; and performing a processing operation to calculate a resistance value indicative of the resistive power loss through the channel between the PSE and PD by: calculating a voltage difference as the difference between the first and second voltage measurements; calculating a current difference as the difference between the second and first current measurements; and dividing the voltage difference by the current difference to generate the resistance value.