Abstract: A system and method for measuring a cable resistance in a power over Ethernet (PoE) application. A short circuit module in a powered device is designed to produce a short circuit effect upon receipt of a cable resistance detection voltage. The cable resistance detection voltage can be designed to be greater than a voltage for detection or classification and less than a voltage for powering of the powered device. The measurement of the current at a time when a short circuit effect is produced at the powered device enables a calculation of the actual resistance of the cable on a given PoE port.