... single-phase prepaid kWh meter, LED display, RF card type, the RF card is inductived in the card slot, ... will be used together with RF card, card machine and software. The card machine is connected with computer by RS232 ... and manager software. 2. the user will take RF card to energy sales department to purchase energy, ... meter in one time, after the energy in RF card has inputed to kWh meter, and then ...