Fire alarm system means any mechanical, electrical or radio-controlled device designed to emit a sound or transmit a signal or message when activated or any such device that emits a sound and transmits a signal or message when activated because of smoke, heat or fire. Without limiting the generality of the foregoing, alarm systems shall be deemed to include audible alarms at the site of the installation of the detection device, proprietor alarms and automatic telephone direct dial devices or digital alarm communicator systems. A single station smoke detector shall not be deemed to be an alarm system under this article.