DSSF3/DTSF3 three-phase multi-rate energy meter applies to measure 3-phase active energy corresponding to different tariffs It realizes data exchange via RS485 network or by HHU, and the data transmission protocol conforms to IEC1107. This meter can measure in different time section, set the daily automatic data revert, program and write the data for the mobile and PC, LCD display. The meter has the characteristics of high accuracy, good stability, wide-load, low power consumption, strong anti-interference ability, etc.