Abstract: Apparatus for automatically controlling the application of the power ring signal of an incoming call generated by the telephone company to a telecommunication device by way of an electronic switching device connected in series with the telephone line. The electronic switching device is controlled by logic circuitry operating in conjunction with circuitry designed to receive and demodulate the caller identification data signal provided by the telephone company during the silent interval between the first and second power ring signals of an incoming call. The logic circuitry maintains the electronic switching device in a nonconductive state, while the telephone company caller identification data received is used to determine whether to continue to suppress the subsequent power ring signals, or allow them to pass to the connected telecommunication device by actuating the electronic switching device to the conducting state.

Abstract: Apparatus utilizing change in pressure condition in an area to be protected to indicate intrusion or change in conditions of the area by means of a pressure detection device to detect pressure waves at low and infrasonic frequencies which includes a pressure transducer sensitive to change in pressure to provide an output signal. In some instances an amplifier is provided to amplify the output signal, a signal conditioning circuit is provided to delay a portion of the signal, and a detector device is provided to detect the signal with a comparator provided to compare the signal with the delayed signal and actuate an alarm.

Abstract: Apparatus utilizing change in pressure condition in an area to be protected to indicate intrusion or change in conditions of the area by using a pressure detection device to detect pressure waves at low and infrasonic frequencies which includes a pressure transducer sensitive to change in pressure to provide an output signal. In some instances an amplifier is provided to amplify the output signal, a signal conditioning circuit is provided to delay a portion of the signal, and a detector device is provided to detect the signal with a comparator provided to compare the signal with the delayed signal and actuate an alarm.

Abstract: Audio frequency signal generator to generate signals in a selected band of audio frequencies to generate a noise having an amplitude pattern which simulates the noise generated by a selected occurrence which can be utilized for setting the actuation range of an audio actuated alarm device which is capable of discriminating the noise generated by such an occurrence where the generated frequency of the sound and amplitude of the sound waves can be varied selectively to simulate the pattern of the sound waves emanating from the selected occurrence.

Abstract: Apparatus utilizing change in pressure condition in an area to be protected to indicate intrusion or change in conditions of the area by using a pressure detection device to detect pressure waves at low and infrasonic frequencies which includes a pressure transducer sensitive to change in pressure to provide an output signal. In some instances an amplifier is provided to amplify the output signal, a signal conditioning circuit is provided to delay a portion of the signal, and a detector device is provided to detect the signal with a comparator provided to compare the signal with the delayed signal and actuate an alarm..Iadd.Additionally, a device producing signals responsive to pressure waves and selected sonic frequencies is taught. If the signals are coincidently received at a coincidence detector, an alarm is activated. Further, the signals can be stretched and/or delayed before receipt at the coincidence detector. .Iaddend.