Alarm system having improved communication
US6426697B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 10, 1999 |
| Grant date | Jul 30, 2002 |
| Priority date | — |
| Expiry date | Nov 10, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B26/001
- WIPO fieldControl
- WIPO sectorInstruments
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. Communication in the active mode is accomplished by reducing the second voltage level to about the first voltage level and sending data pulses along the power lines relative to the first voltage level. According to a further aspect of the present invention, the system controller can synchronize respective timers of each notification appliance wit…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.