Network engineers in campus and enterprise environments have been building a DC network overlay for years in the form of Power over Ethernet. All of those VOIP

Network engineers in campus and enterprise environments have been building a DC network overlay for years in the form of Power over Ethernet. All of those VOIP phones, access points, and security cameras all need DC power with UPS backup and the network closet has become where that power is provided. On our campus it's reaching the point where every switch we'll be buying will soon be PoE. I imagine many places are far ahead of us on this. What is the max cable length of USB Pd?