Test different types of MU in electronic transformer input, magnetic transformer input and electromagnetic transformer input, integrate with reliable analog output and high-speed digital signal process. Support GPS, IRIG-B and PPS timing method, 0.05% high accuracy analog output and strong abnormal SMV function. POM2-3333 can also test SMV accuracy, data process delay, clock synchronization, time accuracy, abnormal SMV and SMV time dispersion,etc items. Functions: Background software can do programming of the electrical wiring graph and configuration and fault simulation of protection relays, analog the setting of specifications of MU, digital terminal devices and specifications setting of fault and fault points. The entire testing and operation process can be controlled by the background software. Two kinds of test modes ensure absolute time delay parameters of MU and complete the SMV response time test accurately. The timing function makes tests on MU's clock synchronization and time accuracy, etc time characteristics. SMV analysis analyzes SMV and GOOSE messages output by MU in real-time. It tests the MU's self-checking and fault process by SMV quality bit, signal remark in GOOSE or the defined warning information in GOOSE. The electric quantity in SMV can display the wave, binary status and previous displacement time. The SMV and GOOSE abnormal output by MU can be judged and analyzed by multi abnormal SMV detection systems. The accurate timing remark on SMV can statistic and evaluate the time dispersion of MU's SMV.