Bidirectional, interactive fire detection system
US4394655A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 13, 1981 |
| Grant date | Jul 19, 1983 |
| Priority date | — |
| Expiry date | Mar 13, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B17/00
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The signalling system disclosed herein transmits groups of pulses to a plurality of transponders, and each transponder recognizes its address in a particular group of pulses. The group of pulses can reset the system, command a transponder to accomplish a specific function, or command the transponder to do nothing. Information returned from the transponder includes a reference voltage, which can be compared in the controller to continuously determine the margin from alarm of an associated transducer. The transponder further provides a signal identifying itself, and pulse duration signals representing analog signals received from one or more transducers associated with the transponders. No end-of-line termination is required, and branching is possible at any point along the loop.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.