Level 1 charging works from a single phase AC power outlet and is suitable for private, domestic installations and these do not need authentication and billing.
If the charger is designed to work with public charging stations, as many Level 2 installations will be, it will most likely need to incorporate further intelligence to communicate with the charging station to verify that the user is authorised to draw power from that particular source and to allow it to bill the customer for the energy transferred unless charging is installed at home or as a free service in the workplace or shopping mall.
Level 2 charging stations may use either single phase or three phase AC power from the grid.
This self contained systems used for Levels 1 and 2 gives the charger the flexibility to connect to different AC charging sources.