Power line communication (PLC) is a kind of communication technology which uses the power line as the communication media. The PLC technology is divided with 2 sub-field: narrow-band PLC and wide-band PLC. For the narrow-band PLC, there are 2 very import standards: Prime and G3. Both the standards are widely used in AMR and electric monitor system and it lead to the rise of threat in AMR system security and electric safety. This topic will talk about how to get the PLC data stream in a PLC communication system which would use G3 or Prime standard, and will also talk about how to detect attacking in the net. We will focus on how to identify which kind of standard the system using and how to sniff the PLC data in physical level.