DDS666 single phase electronic watt-hour meter (hereinafter referred to as watt-hour meter) is designed and manufactured according to the demand of residential users for measuring AC active energy with reference frequency of 50Hz and reference voltage of 220V.

The energy meter meets the relevant requirements of GB/T17215.321-2008 "Static energy meter Communication Protocol (Level 1 and 2)", DL/T645-1997 "Multi-function energy meter Communication Protocol" and other standards.