Smart Meters are defined as those digital electric power meters that have a transmitter and a receiver with which they can communicate to a controller unit.  The controller can send commands to the Smart Meter via the Smart Grid and then receive responses from the selected Smart Meter also via the Smart Grid.  The Smart Grid is just all of the Smart Meters that can relay messages between the Controller and any selected Smart Meter.

The communication protocol is not readily available on the WEB but it is though to be something like the following which is similar to computer dialog between devices using IP addresses:

Controller – Meter #33 – are you there?

Meter #33 – Yes, I am ok and there are no alarms triggered

Controller – Meter #56 – send me the hourly kWh readings now.

Meter #56 – OK boss, here are the kWh readings and the alarm status.