(Machine to Machine)
In the world of cell phone networks, M2M refers to devices other than cell phones using the wireless network to communicate with other devices or networks.
Typically, a small device known as an M2M module is embedded in a larger device that needs to communicate over the wireless network. The M2M module contains the same type of radio and data circuits that would be found in a typical cell phone, but nothing else (no display or keypad, etc.)
M2M modules can be embedded in things such as vending machines, automobiles, alarm systems, and remote sensors.