Provided are a memory device testing apparatus and method of operating such an apparatus that can reduce the time required to test a memory device such as a DRAM. The three sets of local PMU measurements at each terminal are used for online calculation of a respective Thevenin Equivalent. Further, according to certain embodiments, the access point has the intelligence to switch over from a CAPWAP over a Datagram Transport Layer Security protocol to a CAPWAP over HTTP protocol when the access point detects a firewall between the access point and the corresponding cloud controller.