GSM is currently the second most popular transmission path for alarm systems after PSTN landlines. Cellular and IP will eventually replace landlines and GSM will play a very important role in the transition.
There are three different methods of sending alarms over a GSM network. Voice, SMS and GPRS. SMS is currently the most popular in the USA, however, IP Alarms are encouraging the use of Voice and GPRS to provide more functionality and increased levels of security.
Short Message Service (SMS) is a quick and simple method of sending alarm messages over a wireless GSM network. The IP Alarms CellAlarm-SMS has a series of alarm inputs that can be triggered from alarm panel outputs. SMS alerts can be sent to a monitoring center and direct to a cell phone. It is essential to choose a reliable network provider as SMS messages can sometimes suffer from long delays. You should understand that there is no way for the monitoring center to know if the GSM network becomes unavailable.
The voice channel of a GSM modem can be used to make a phone call to an alarm receiver at a monitoring center over a cellular GSM network. This allows your alarm panel modem to communicate with the alarm receiver wirelessly, just as it would normally over a fixed line connection. This method of signalling is especially popular with the DIY community as there is no way for the monitoring center to know if the call to their alarm receiver came over PSTN or GSM. You should understand that there is no way for the monitoring center to know if the GSM network becomes unavailable.
The data channel of a GSM modem can be used to make a permanent wireless connection to the Internet over a GPRS enabled network. The CellAlarm-GPRS device can send out regular heartbeats to the server for supervision purposes and transmit alarm messages in around two seconds. It is also easy for the Central Station to remotely program the GPRS communicator via management software should any parameters need to be changed.