A security system uses the telephone line for communications to central station during an alarm condition. If there would be a telephone line failure or tampering with a line, the security panel would not be able to alert central station of the alarm condition.
A cellular backup by AlarmNet provides a secondary method of communications (RF) to central station during an alarm condition. Since the cellular backup unit is located within the home, it is more tamper resistant. AlarmNet cellular monitoring will increase your monthly monitoring rate, but can provide a much higher level of security because your system has two methods of communication.