Cellular monitoring works by installing a module to the Control Panel of the Alarm or Fire Alarm system.  This cellular device acts as the communicator between your system and the monitoring station.  The module sends the signals using regular cellular towers.  The cellular signal is sent through the Data portion of a cellular signal, much like a text message, as opposed to the Voice signals that are used by traditional cellular phones.  This allows the cellular alarm signal to reach the monitoring station quickly and without disruption.