Abstract: The present invention is a communications system comprising a host device and an external device or product having a 4 byte Product ID. The host device is adapted to poll the external device to determine the Product ID of the external device. The external device is adapted to transmit its 4 byte Product ID to the host device in response to the Product ID Request from the host device. The host device is adapted to generate a packet having an authentication command 0×1 F followed by a pair of CRC bytes having a CRC_HI byte and a CRC LO byte. The pair of CRC bytes take into account the 4 byte Product ID and the authentication command 0×1 F when generating an overall value. The 4 byte Product ID is not contained in the packet. The host device 12 is further adapted to transmit the packet to the external device 14. The external device is further adapted to authenticate the packet, and if authenticated, provide the host device with full command and control of the external device 14.

Abstract: A processor, such as a microprocessor, responds to the detection of an input audio signal generated by glass breakage to cause an alarm to be indicated, such as at a remotely located alarm control panel. The system determines when the input power supply voltage supplied to the system falls below a selected low voltage level. The system is placed in a test mode of operation in response to a uniquely characterized, humanly generated input sound signal and then can be tested by any appropriate humanly generated input sound signal. The system continually monitors ambient background noise and determines when an absence thereof occurs so as to provide an indication of such absence to alert the user to the possibility that the system may have been purposely comprised. The system further uses a number of indicators arranged so that the meanings thereof are different depending on whether the system is in an alarm detection mode of operation or in a test mode of operation.