1. A method for preventing harmful transients resulting from a probing routine for a valid powered device detection signature in a network, the method comprising: providing a pre-detection voltage to the output port of a power sourcing equipment via an impedance, said provided pre-detection voltage restricted so that voltage at the output port in the absence of a load across the output port is less than a predetermined threshold at which damaging transients can occur, said predetermined threshold less than or equal to 5 volts; obtaining an indication of voltage at the output port of the power sourcing equipment responsive to said provided pre-detection voltage; comparing said obtained indication of voltage at the output port of the power sourcing equipment responsive to said provided pre-detection voltage with a pre-determined value; and initiating, only in the event that said obtained indication of voltage at the output port of the power sourcing equipment responsive to said provided pre-detection voltage is less than said pre-determined value, a probing routine for a valid powered device detection signature.