For those wanting the protection of a Complete Home Security Alarm System but lacking a land line telephone. The ABS Cellular Alarm System consists of a Wireless Home Security Alarm System matched a with Cellular Gsm Terminal operationing on all major world band frequencies. This GSM Alarm System is perfect for vacant and weekend homes,construction sites....anywhere with power but no phone line. Self monitored. No fees or contracts. Expandable [to 96 sensors]and portable. The GSM Alarm System operates on all major world band cellular frequencies: 1. GSM 850 mhz/900mhz/1800mhz/1900mhz 2.GSM 900mhz/1800mhz 3. CDMA 800 MHz The GSM Terminal replaces the typical landline and works like a cell phone. As most mobile phones utilize a SIM card to wirelessly transmit through the cellular network so does the Cellular GSM Terminal. SIM cards may be purchased as a prepaid card or on a monthly basis from your cellular carrier such as AT&T and T-Mobile. The GSM Alarm System comes with a built-in backup battery pack and the GSM Terminal has the option of a UPS Back-up Battery power adapter to maintain continuous fuctioning in case of power outages and interruptions. The GSM Alarm does not interfere with Wi-Fi applications. The Cellular Alarm System will call to mobile phones, landline phones and broadband phones. The Cellular Alarm System comes with an integrated Automatic Dialer with a stored memory capacity for six phone numbers[up to 21 digits in length] and for a recorded message. When the Wireless GSM Alarm System is triggered it will call each of the pre-stored numbers and deliver the pre-recorded message. When the system calls, the receiver will be able to listen and monitor the premises through the phone more info