Automatic meter-reading technology have 3 kinds: special line technology, wireless technology and power line carrier (PLC) technology. The 2 former is common, which is difficult to promote due to high cost and difficult installation; the latter adopts power line as medium, easy installation and low cost, this technology has very bright potential. SYSTEM ELEMENT AND INSTALLATION This system includes central computer, Remote Collecting Unit (RCU) and energy meters (Electronic meter, Multi-function meter and Mechanical meter), a communication module is inside the meter. Central computer communicate RCU though telephone line and Modem; and RCU communicate with energy meter thought low-voltage power line. ADVANTAGE: PLC meter-reading system is new generation system developed from PLC technology, which has following advantages compared with similar domestic and overseas products: 1. System project products Domestic and overseas similar products just solve the meter-reading problem, however PLC consider possibility of problems. We design the system as a system project and supply the measurement and equipment to solve the present problems, relevant problems and future problems. Especially we supply administrative software to control and analyze power theft, meter breakdown, charge notes, etc. 2. Most advanced PLC technology The similar products adopt pure frequency amplifying PLC technology, which is very strict to power line condition, clean and no disturbance. Usually most power line is not in clean condition completely, however QJPLC system adopts ambiguous frequency amplifying PLC technology to ensure high communication reliability and stability. 3. Accurate counter: 0 error counter 4. Relay function Common PLC products have a communication distance limit, however for QJPLC products the meters (communication module) can relay/support one another, and increase the communication distance so much. 5. Freeze function When the system freeze the users, it can records the freezing time the present power consumption. This function can adjust peak consumption area to increase the power net efficiency. 6. The best coding system Most meter-reading system need to set the meter address code, this code system is difficult to maintain, when the scale becomes large, wrong code is inevitable, and make changing meter and charge difficult. QJPLC system adopts the meter series No. or user No. as meter address code, it is easy to maintain and administrate. 7. Special search function Administrative staff can search users accurate location, this function can not be affected by change of power net structure, when the user move to other area (transformer), the system can find and inform the administrator. 8. Low investment First our gain is to reduce the cost of the equipment needed in large quantity, and reduce the quantity of experience equipment; moreover the system adopt power line as medium, no need to invest to set up special line and experience wireless equipment; later on our module is suitable for all kinds of meters. 9. Easy installation Less line connection, no need to install any special line, which is the lest installation products. 10. Intelligent RCU RCU can memory the power net structure and analyze the reading results and memory each meter phase position and related position automatically, in pace with more memory and analysis, the system keeps self diagnostics, once a certain meter has not been read, the system will choose the best relay