If you have managed network switches that support LLDP (Link Layer Discovery Protocol) or CDP (Cisco Discovery Protocol), this device follows the feedback and tells you which switch port the network wall port is connected to connected is. It will also tell you if the network cable is good (no terminator on the other end) and how long the cable is. If you need to freeze parts of the network that others have left in tatters because of lousy documentation or crappy cables, this is the device for you. This halves the test time. Notes: - LinkRunner also works as a tone generator. You should probably buy an Intellitoner Pro 200 to use if you need to toning cables or switching ports. The high-end LinkRunner AT 2000 also runs fiber and some PoE tests, and comes with a battery that's insanely expensive and hard to find as an add-on. If you don't need to test fiber and are fine with using alkaline batteries, the AT 1000 will do. I have a pair of stacked Dell switches that are fiber optic connected to another Dell switch where this tester is traced back to the fiber. the uplink of the main switch, not the Cat5 ports of the stack. Unfortunately Dell won't help me without ProSupport so I'm stuck. It could be a Dell or Fluke problem; I deduct a star for that.