Abstract: A telephone line interface and side-tone attenuation circuit includes two opto-electric converters. The first has an input interconnected to receive a signal proportional to a near-end signal, and an output interconnected to modulate a current proportional to the near-end signal onto the subscriber loop. The second has its input interconnected to provide a signal proportional to a current on the subscriber loop, including the current proportional to the near-end signal, at its output. A summing amplifier receives signals proportional to the output voltage of the second opto-electric converter and a signal proportional to the near-end signal. The output voltage of the second opto-electric amplifier includes a component that is substantially 180° out of phase with the near-end signal, allowing the near-end signal to be cancelled at the summing amplifier.

Abstract: An alarm panel of a security system is additionally provided with an interference circuit for evaluating the possible presence of a large electromagnetic interference signal such as lightning. The earth ground connection of the alarm panel to a power source is used to provide an input to the interference circuit. The earth ground connection receives large transient signals caused by such naturally occurring events. The alarm panel uses this additional information to modify the reporting of alarm conditions. This has particular application for addressing problems associated with motion detectors falsely triggering when a large electromagnetic signal is received. The solution of the alarm panel sensing this condition in contrast to each detector sensing this condition is more reliable, allows combining of detector information and is more cost effective.

Abstract: An alarm panel of a security system is additionally provided with an interference circuit for evaluating the possible presence of a large electromagnetic interference signal such as lightning. The earth ground connection of the alarm panel to a power source is used to provide an input to the interference circuit. The earth ground connection receives large transient signals caused by such naturally occurring events. The alarm panel uses this additional information to modify the reporting of alarm conditions. This has particular application for addressing problems associated with motion detectors falsely triggering when a large electromagnetic signal is received. The solution of the alarm panel sensing this condition in contrast to each detector sensing this condition is more reliable, allows combining of detector information and is more cost effective.

Abstract: A high frequency bypass circuit is advantageously used in combination with a security system control panel. The bypass circuit divides telephone signals provided to the circuit into a low frequency DC signal and a high frequency AC signal, typically used for data transfer. The DC signal is provided to the security system alarm control panel and the high frequency AC signal bypasses the control panel, and is connected to the private telephone system. Conventional phones on the private telephone system can be disconnected by the control panel while any high frequency signal continues uninterrupted.

Abstract: A security system having two distinct channels of communication and which uses a single communication device provides improved security. The system monitors a host of security alarm panels connected to a telephone system. A status signal is communicated between each control panel and a scanner placed at a switching station of the telephone system to confirm the integrity of the communication channel. An alarm event continues to be reported to a monitoring station using the telephone system in the normal manner.

Abstract: A dual element PIR detector for a security system uses a series of beams in selected areas to limit the amount of radiation received from small domestic pets. A series of alternating beams define dead zones and the beams and dead zones provide size discrimination where a small domestic cat or other small pet does not have sufficient size to cause IR responses in two sensors sufficient to cause an alarm condition.

Abstract: A security system having a two way wireless keypad which operates in a particular manner for improved operation. The keypad processes information to effectively reduce communications between the control panel and the keypad. The keypad selectively activates and deactivates a transmitter and receiver arrangement for power conservation reasons. The system provides confirmation of communications between the keypad and the control panel to increase the reliability of the system.

Abstract: An arrangement and method for processing signals from infrared microwave and/or ultrasonic intrusion detectors is disclosed which allows the signal to be processed at different amplitude levels to recognize different signal characteristics. This capability to analyze the signal at different values allows further customizing of the system for particular applications and provides information useful in recognizing and dealing with unwanted signal changes typical of the environment which can effect the reliability of the alarm criteria and/or a trouble condition criteria. An assessment of the environment in a preferred aspect allows customizing of the alarm criteria to take into account the operating environment of the particular sensor or sensors. The system also accommodates increasing the effect on certain portions of the signal when considering the net overall effect of the signal.

Abstract: An arrangement and method for processing signals from infrared intrusion detectors is disclosed which allows the signal to be processed at different amplitude levels to recognize different signal characteristics. This capability to analyse the signal at different values allows further customizing of the system for particular applications and provides information useful in recognizing and dealing with unwanted signal changes. The system also accommodates increasing the effect on certain portions of the signal when considering the net overall effect of the signal. This results in more signal information being available and higher accuracy in detecting actual human intrusions in the monitored space.

Abstract: The present invention is directed to an intrusion detection system having two different types of motion sensors and processing of the signals produced by the motion sensors in a manner to provide a reliable indication of motion within the space being sensed. The intrusion detection system includes a microprocessor and produces an alarm signal if each sensor is activated within a predetermined time period of each other. The unit is also capable of producing what is referred to as a "trouble" signal, based upon a certain number of unconfirmed event signals, i.e. a signal from only one sensor being received, within a predetermined time, indicating that one of the sensors is not operating properly. Once a certain number of unconfirmed event signals are received, the unit operates in one of at least two different default modes whereby a trouble signal or trouble signal and alarm signal are produced by means of a different logic processing step.