Abstract: In a fire alarm system, a message is sent on a pair of power lines to a notification appliance. The notification appliance responds to the message by activating one or more of its notification devices. In a standby mode, only enough power is supplied to the plural notification appliances, at a first voltage level, to support two-way communications between a system controller and the notification appliances. In an active mode, power is supplied at a second voltage sufficient to operate audible and visible alarms of the notification appliance.

Abstract: In a building fire alarm system, the light strobes of a network of strobes are synchronized to flash simultaneously. Each strobe has a charging circuit to charge a capacitor which discharges through a flash tube. Once a capacitor is charged, the charging circuit is disabled. A synchronization pulse is applied through common power lines to trigger discharge of each strobe capacitor through the flash tube followed by recharging of the capacitor.

Abstract: The present invention relates to an audio signal sound diffusion system for diffusing, e.g., alarm signals, pre-recorded signals and microphone signals over wide areas. According to one of its aspects, the present invention relates to an audio signal sound diffusion system characterised in that it comprises: at least one diffuser (35a–38a, 35b–38b); at least one amplifier (31–34) connected to said diffuser (35a–38a, 35b–38b); a generation circuit (27) for generating at least one audio signal connected to said amplifier (31–34); a control circuit (10) for controlling said sound diffusion system adapted to detect the malfunctions of said diffusion system and to generate a status alarm (14) of said diffusion system; connection means (17, 40) adapted to connect said control circuit (10) to a management system; said control circuit (10) is adapted to send to said management system at least one status alarm (14) of said sound diffusion system.

Abstract: In a building fire alarm system, the light strobes of a network of strobes are synchronized to flash simultaneously. Each strobe has a charging circuit to charge a capacitor which discharges through a flash tube. Once a capacitor is charged, the charging circuit is disabled. A synchronization pulse is applied through common power lines to trigger discharge of each strobe capacitor through the flash tube followed by recharging of the capacitor.

Abstract: In a building fire alarm system, the light strobes of a network of strobes are synchronized to flash simultaneously. Each strobe has a charging circuit to charge a capacitor which discharges through a flash tube. Once a capacitor is charged, the charging circuit is disabled. A synchronization pulse is applied through common power lines to trigger discharge of each strobe capacitor through the flash tube followed by recharging of the capacitor.

Abstract: In a building fire alarm system, the light strobes of a network of strobes are synchronized to flash simultaneously. Each strobe has a charging circuit to charge a capacitor which discharges through a flash tube. Once a capacitor is charged, the charging circuit is disabled. A synchronization pulse is applied through common power lines to trigger discharge of each strobe capacitor through the flash tube followed by recharging of the capacitor.

Abstract: In a building fire alarm system, the light strobes of a network of strobes are synchronized to flash simultaneously. Each strobe has a charging circuit to charge a capacitor which discharges through a flash tube. Once a capacitor is charged, the charging circuit is disabled. A synchronization pulse is applied through common power lines to trigger discharge of each strobe capacitor through the flash tube followed by recharging of the capacitor.

Abstract: In a building fire alarm system, the light strobes of a network of strobes are synchronized to flash simultaneously. Each strobe has a charging circuit to charge a capacitor which discharges through a flash tube. Once a capacitor is charged, the charging circuit is disabled. A synchronization pulse is applied through common power lines to trigger discharge of each strobe capacitor through the flash tube followed by recharging of the capacitor.

Abstract: In a building fire alarm system, the light strobes of a network of strobes are synchronized to flash simultaneously. Each strobe has a charging circuit to charge a capacitor which discharges through a flash tube. Once a capacitor is charged, the charging circuit is disabled. A synchronization pulse is applied through common power lines to trigger discharge of each strobe capacitor through the flash tube followed by recharging of the capacitor.

Abstract: An alarm system is provided which includes multiple notification appliances for signaling an alarm condition. The system controller intelligently controls the notification appliances including notification devices such as an audible or visual alarm through multi-bit digital messages sent over communication lines. The alarm system has both a standby and active mode of operation in which communication between the controller and notification appliances is possible in both modes of operation. In the standby mode, the notification appliances are powered at a first voltage level. Communication between the notification appliances and the system controller is provided by sending data pulses along the communication lines relative to the first voltage level.

Abstract: An alarm system is provided which includes multiple notification appliances for signaling an alarm condition. The system controller intelligently controls the notification appliances including notification devices such as an audible or visual alarm through multi-bit digital messages sent over communication lines. The alarm system has both a standby and active mode of operation in which communication between the controller and notification appliances is possible in both modes of operation. In the standby mode, the notification appliances are powered at a first voltage level. Communication between the notification appliances and the system controller is provided by sending data pulses along the communication lines relative to the first voltage level.

Abstract: A shield for a wall mounted smoke detector guard or enclosure prevents looped items from being hung on the shield and the enclosure. The shield includes a mounting surface for mounting to a wall. A downwardly sloping surface structure extends from the mounting surface for extending above the top surface of the enclosure. The downwardly sloping surface structure has sufficient slope and length for preventing items from being hung on the shield and the enclosure while at the same time providing a direct smoke flow path therepast to the top surface of the enclosure.

Abstract: An integrated security system (10) for monitoring a premises (12) to detect an intrusion onto the premises comprises a video system for providing video representations of the premises, an alarm system for providing an indication of an intrusion onto the premises, an access control system for allowing authorized entrance onto the premises, a processing device connected to the video security system, the alarm system, and the access control system for producing a signal indicative of an intrusion onto the premises, and a monitoring center connected to the processing device for receiving the signal indicative of an intrusion onto the premises.

Abstract: Jumper and ground faults are detected within an alarm system. Jumper detection applies to devices having two or more functions (e.g., audible horn and visual strobe). When operated with a single circuit, jumpers typically remain installed in such devices to provide power to all functions. However, if the devices are installed in alarm systems equipped with multiple functions, the jumpers should be removed to allow functions to operate independently and correctly. To detect unremoved jumpers, all loops to separate functions except one are isolated. After isolation, a predetermined signal is presented to the non-isolated loop and current is compared to a reference value. If jumpers exist between this non-isolated loop and another supposedly isolated loop, the additional parallel resistance produces an abnormal signal. To perform ground fault detection, lines of devices may be sequentially isolated (i.e., disconnected) at the control panel via software control until a previously detected ground fault disappears.

Abstract: An alarm system is provided which includes multiple notification appliances for signaling an alarm condition. The system controller intelligently controls the notification appliances including notification devices such as an audible or visual alarm through multi-bit digital messages sent over communication lines. The alarm system has both a standby and active mode of operation in which communication between the controller and notification appliances is possible in both modes of operation. In the standby mode, the notification appliances are powered at a first voltage level. Communication between the notification appliances and the system controller is provided by sending data pulses along the communication lines relative to the first voltage level. In an active mode of operation, the first voltage level is raised to a second voltage level.

Abstract: A site control unit (12) located at a premises (F) processing video images obtained from a plurality of cameras (22) located about the premises and relaying the presence of a real intrusion to a central station (CS). The site control unit has an image acquisition module (24) receiving video images from the cameras. An image processor (30) processes the images to eliminate possible causes of false alarms of an intrusion and reliably detecting actual intrusions. The processor includes video masking (32) to filter known motion present within a scene, detection (34) detecting movement in unmasked portions of the scene, and recognition (36) classifying the cause of the movement. An indication of an intrusion is given only if the cause is one of a class of predetermined causes representing an intruder on the premises, or an unknown cause. A video recorder (38) records images of the actual intrusion and supplies recorded images to a security system operator (O) who informs authorities of in intrusion.

Abstract: A building alarm system includes addressable notification appliances connected to a system controller, with each notification appliance having a status indicator and an alarm indicator. The status indicator, such as an LED, provides for system test modes that avoid disruption of building occupants. To test the alarm system, the system controller selects which notification appliances to operate in response to a test alarm input and communicates to each selected appliance an instruction to operate its associated status indicator without operating its associated audible or flashing visible alarm indicators. In a troubleshooting mode, the system controller polls each of the notification appliances and receives an answer in response to the poll from any of the appliances. The controller operates the LED indicators of those appliances which answer the poll.