Check your RJ-45 outlet for power using the Power Dsine Po E Tester The Power over Ethernet (Po E) Tester, connected to an RJ-45 outlet, tests the cabling infrastructure for the presence of power, either IEEE802.3af standard-compliant or pre-standard. The Po E Tester identifies the existence & type of Power Sourcing Equipment (either Endspan or Midspan)in your network.