This standard specifies communications for low frequency (less than 500 kHz) narrowband power line devices via alternating current and direct current electric power lines. This standard supports indoor and outdoor communications over low voltage (less than 1000 V (LV) and medium-voltage (1000 V up to 72 kV) (MV) power lines and through associated in both urban and in long-distance rural applications. The standard uses transmission frequencies less than 500 kHz. Data rates will be scalable to 500 kbps depending on the application requirements and network conditions. This standard addresses grid to utility meter, grid automation, electric vehicle to charging station, and within home area networking communications scenarios. Lighting and solar panel power line communications (PLC) are also potential uses of this communications standard. This standard focuses on the balanced and efficient use of the PLC channel by all classes of low-frequency narrow band devices, defining detailed mechanisms for coexistence between different low-frequency narrow band standards developing organizations (SDO) technologies, assuring that desired bandwidth may be delivered. This standard assures coexistence with broadband power line devices by minimizing out-of-band emissions in frequencies greater than 500 kHz. The standard addresses the necessary security requirements for communication privacy and allow use for security sensitive services. This standard defines the physical layer (PHY) and the medium access sub-layer (MAC) of the data link layer, as defined by the International Organization for Standardization (ISO) Open Systems Interconnection (OSI) Basic Reference Model.