Abstract: In one aspect, a phone-interface device determines whether a problem has occurred at a control panel by determining whether a signal from the control panel has been received, and when a signal has not been received within a period of time, the phone-interface device transmits an error message to a monitoring station. In another aspect, the control panel determines whether a problem has occurred at the phone-interface device by determining whether a signal from the phone-interface device has been received, and when a signal has not been received within a period of time, the control panel transmits an error message to a user. In another aspect, the phone-interface device contains memory to buffer data transferred between the control panel and a monitoring station. In this way, a high-speed connection between the phone-interface and the monitoring station can be accommodated while using a lower-speed connection between the phone-interface device and the control panel.

Abstract: A PIR sensor apparatus and method make use of a dc amplifier circuit. The dc amplifier circuit amplifies a dc-coupled sensor signal generated by a PIR sensor for analysis. For improved accuracy, the dc amplifier circuit is controlled to compensate for dc offset in the sensor signal. In this manner, the dc amplifier circuit is capable of reducing false triggering and inhibited triggering due to excessive dc offset. The amplifier is dc-coupled to an output of the PIR sensor to receive the sensor signal. A detector detects a level of dc offset within the sensor signal. A controller controls the amplifier to compensate for the detected level of dc offset The amplifier may include a differential amplifier having a first input that receives the sensor signal and a second input that receives a reference voltage. A resistor-capacitor circuit can be provided to set the reference voltage received by the second input of the amplifier.

Abstract: A detection system and method are capable of reducing the occurrence of false alarms and detection failures by compensating for variations in the amplitude of a detection signal generated by a PIR sensor. An adaptive threshold can be used that varies according to ambient temperature of the detection area and the frequency of the detection signal. Comparison of the detection signal to the adaptive threshold allows compensation for temperature-and/or frequency-induced variations in detection signal amplitude. The adaptive threshold can be configured for standard detection area conditions or calibrated for conditions at the installation site. Relative measurement and adaptive sampling techniques also can be used to compensate for the presence of low frequency shifts in the detection signal. Such techniques can provide an accurate representation of signal amplitude relative to a threshold amplitude despite differences in absolute signal magnitude.

Abstract: A security system and method for building complexes having multiple units provides enhanced resistance to intruder disablement, particularly for systems having a unit controller and user input device that are mounted within a common control panel. The system and method are useful with residential building complexes having residential units such as apartments and condominiums, and commercial building complexes having commercial units such as offices, businesses, or storage facilities. A unit controller communicates a unit alarm condition to a main controller located remotely from a respective unit. The unit alarm condition can be communicated via wireless communication. Also, the unit alarm condition is communicated without significant delay following the sensing of a security condition in the unit. For example, the unit controller can communicate the unit alarm condition to the main controller substantially immediately following sensing of the security condition.

Abstract: In a wireless security system, the system controller includes one or more antennas for reception of signals from remote sensor-transmitter units. To detect antenna failure, the system controller generates a test signal with a known parameter and transmits this test signal via a first antenna. The system controller then measures the parameter of the corresponding test signal received, if any, via a second antenna, and compares the parameter of the corresponding test signal received to a predetermined threshold parameter. When the parameter of the test signal received via the second antenna differs from the threshold by a predetermined amount, or predetermined margin for error, an antenna failure message is generated.

Abstract: Measuring the critical value of a parameter of a sensor in a security system (e.g., battery voltage) is performed at a time when the critical value is most likely to be reached, and the critical value information is sent from the sensor to a system controller at a time when the information is most likely to be successfully received.

Abstract: An apparatus and method for reducing errors in a battery powered sensing circuit uses two pull-up resistors. The first resistor has a value selected to minimize battery drain and the second resistor has a value selected to reduce dendrite or other parasitic parallel resistance. The resistors are selectively connected to the circuit based on a predetermined sequence and/or time interval.

Abstract: A detection system and method are capable of reducing the occurrence of false alarms and detection failures by compensating for variations in the amplitude of a detection signal generated by a PIR sensor. An adaptive threshold can be used that varies according to ambient temperature of the detection area and the frequency of the detection signal. Comparison of the detection signal to the adaptive threshold allows compensation for temperature- and/or frequency-induced variations in detection signal amplitude. The adaptive threshold can be configured for standard detection area conditions or calibrated for conditions at the installation site. Relative measurement and adaptive sampling techniques also can be used to compensate for the presence of low frequency shifts in the detection signal. Such techniques can provide an accurate representation of signal amplitude relative to a threshold amplitude despite differences in absolute signal magnitude.

Abstract: Information in the form of redundant message packets is sent between a remote device and a host device, e.g., a wireless security system. In order to conserve energy, the frequency of trigger events in the remote device is determined, and the number of redundant message packets sent is based on the determined frequency.

Abstract: An apparatus and method for sending messages from a sensor to a system controller in a wireless security or monitoring system, including processing signals from the sensor and generating message packets which include information derived from the sensor signals.

Abstract: A security system sensor has a lens lying in a forward plane that focuses received energy to a focal point that is internal to the sensor. A sensing element is located at or near the focal point of the lens. A funnel-shaped chamber between the lens and the focal point is substantially vacant so that received energy is received by the sensing element. A battery housing is positioned so that the physical volume of a battery power source contained therein is mainly rearward of the lens and the vacant funnel-shaped chamber, yet forward of a plane that is immediately rearward of the sensing element. Also, a dividing barrier, interposed between the chamber and the battery power source, extends to and seals with the sensing element and the lens, thereby providing a seal for the vacant, funnel-shaped chamber.

Abstract: A transformer system couples a control panel with a power line to support two-way communications over the power line. A first transformer steps-down the power line voltage, supplying power to the control panel. A second transformer and associated capacitors provide a low impedance path at the communication signal frequencies and a high impedance path at the power frequency.

Abstract: In a security or monitoring system having a system roller and one or more sensor/transmitters, information is sent from the transmitter to the system controller in message packets. As improved message packet protocol provides a front porch pulse, a set of synchronization bits, a start bit, a set of information bits, a first stop bit, a set of error detection bits, and a second stop bit.

Abstract: A security alarm system including multiple, zone distributed audio monitors and alarm sensors which report and verify detected alarms and communicate with a system controller and central station. Ambient audio is continuously and selectively recorded in a storage memory and is replayable to verify alarms detected at the alarm sensors. During pre-alarm conditions, all audio inputs are summed and recorded. During an alarm state, the audio input of the audio monitor physically closest to a reporting alarm sensor is automatically selected and the post-alarm audio activity is recorded only for that sensor. The central station is able to selectively communicate via a phone link with each audio controller and engage in half duplexed voice communication with the alarm site, remotely playback and listen to the locally recorded audio data, or program each audio controller. The monitored audio data is stored in RAM storage in discreet segments corresponding to predetermined periods of pre-alarm and post-alarm data.

Abstract: In a battery-powered sensor such as a smoke detector, a passive report of unacceptable battery condition is first given while an active report of such condition is inhibited. Then, after the lapse of a period of time after the unacceptable battery condition is first detected, the active report is given.

Abstract: In a security system having a remote monitoring station, a sensor is tested when the security system is in a normal operating mode. The sensor is tested by actuation of a button on the sensor. Actuation of the button generates a signal indicating that a test has been conducted. Upon the generatation of both an alarm signal generated by the test and a signal indicating that a test has been conducted, the security system determines that the alarm signal was generated by a test of the sensor and not by the detection of alarm conditions by the sensor.

Abstract: An improved short distance, battery powered, amplitude modulated RF transmitter for transmitting encoded security data. An oscillator stage provides a control crystal and filter which are feedback coupled between the emitter and base of a transistor to oscillate at the fifth overtone of the fundamental crystal frequency. A filter tuned to the third harmonic of the overtone frequency selects the carrier frequency which is coupled via a resistive attenuator to an amplifier/filter stage, before the carrier is amplitude modulated with encoded security data. The improved transmitter circuit compensates for crystals exhibiting variations in series resistance and provides increased output power and improved frequency stability to temperature and over time. A foil antenna stage is augmented with the plates of the battery power supply to further improve performance.

Abstract: An active, relatively high gain, low power consuming band pass filter circuit centered at approximately 6 KHZ and having a pass band of 100-200 HZ. In a disclosed glass breakage sensor, the filter couples sensed ambient sounds of breaking glass to associated detection, driver and annunciator means. Signals of appropriate duration and frequencies indicative of breaking glass are thereby monitorable to define and induce an alarm condition within a security system.

Abstract: A security alarm network including a plurality of microprocessor-based, subscriber system controllers, wherein each controller is capable of responding to a plurality of distributed wireless and hardwired sensors/transducers and is programmable via user, central station and installer-entered system and network parameters.

Abstract: A time multiplexed integrated alarm contact for reporting detected alarm conditions to a system controller in a hardwired alarm system and wherein distinguishable binary frequencies are used for synchronizing/responding and for programming the contact. During programming, an identity code is written into an included shift register and non-volatile memory defining the system reporting interval and the contact's reporting interval within the system interval. Controller initiated synchronizing signals induce each contact's status transmission with or without resetting an alarm buffer and whereby redundant alarm reports may be obtained.