DDSY23 Electronic Single-phase Prepayment Energy Meter is used to measure single-phase energy with 50/60Hz rated frequency. It realizes the functions of prepayment management and load control that pay of energy first & use it afterwards. It conforms the standards of GB/T 17215-2002 GB/T18460.3-2001. Function: This meter supports one meter with more cards and one card with more meters; however, it just receives the ruled legal card of internal system, an the out card cannot be used. This meter can be used in the hotels, schools, government organizations, business markets or public facilities where have many fluid people and uncertain users and it can also be used in agriculture irrigation. The manager can sell power through power-selling system. The customer inserts the user card which purchased the power into the energy meter to realize purchase power in advance. When the power which the customer purchased run out, the energy meter will cut the power automatically, and the customer has to purchase power again in order to use power. At the moment, when the customer pulls the user card, the energy meter cut power immediately. The whole power-using information of the customer is storage in the user card, so the manager can read the power-using information of the customer by power-selling system in order to do the operation of charge and so on. Applicable condition: Ambient Temperature: -20'C-65'C