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: operating power sourcing equipment to provide via its output port a pre-detection output voltage; obtaining an indication of said pre-detection output voltage; comparing said indication of said pre-detection output voltage with a pre-determined value; and in the event that said indication of said pre-detection output voltage is less than said pre-determined value; initiating a probing routine for a valid powered device detection signature.