The communication between the electricity meter and the SGCom application goes through several layers - physical, relational, and application.
The physical layer of communication defines which physical communication interface of the electricity meter is used for communication (see Figure 1). In the D2000 system, the communication protocol in the Line object has an analogous role.
The relational layer of communication is in charge of maintaining the communication session, i.e. ensuring a consistent flow of data over an unreliable physical layer and also addressing the communicating partners. In the D2000 system, the communication protocol in the Station type object has a similar role.
The application layer transmits specific commands and responses regarding the measured values and the control of the electricity meter. In the D2000 system, the communication protocol also has a similar role in the Station object.
Figure 1 - Different examples of physical connection to electricity meters