Bolster the reliability of your dial-up alarm control panel by connecting a Napco StarLink 3 GSM Wireless Alarm Communicator (AT&T Compatible). This universal two-way communicator works with control panels that communicate using cell phone lines to ensure signal transmission to your preferred central monitoring station. Whether you need backup in case the line goes down, or you have no phone line at all, the StarLink communicator is your solution for dependable security. Because the communicator sends and receives signals over a nationwide GSM cellular network, your connected control panel will be able to communicate with your monitoring station even when disconnected from a landline. Alarm signals are transmitted on the RF data-only portion of the GSM digital network, providing fast, dependable communication with the central station. CONTENTS: Communicator, Antenna, SIM Card.