This test may be performed with any TestPro using the AD-NET-CABLE adapter or with any Network Service Assistant using the AD-NSA adapter. PoE switches are very efficient tools to run devices over Ethernet. But when there is an issue, it might become cumbersome to conclude what's wrong with your. POE is made possible by using a specialized device called a Power Sourcing Equipment (PSE) which is installed in the network switch. The new PoE Pro eliminates guesswork and. In most environments, technicians “test” PoE by connecting the powered device (PD). However, when PoE fails, it can disable critical infrastructure like IP phones, wireless access points, and security cameras. This guide provides a step-by-step troubleshooting.