Continuity-isolation testing for class A wiring in fire alarm system
US4954809A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 1, 1989 |
| Grant date | Sep 4, 1990 |
| Priority date | — |
| Expiry date | May 1, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/06
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A fire alarm system in which a large number of terminal units, comprising detectors and interface circuits, at a variety of locations are coupled or connected in separate, independent loops of the system, each of the scattered terminal units being addressable from a central control panel. The arrangement is such that serial synchronous power transmission and data communication is effectuated over the individual loops of the system. The improvement resides in providing continuity-isolation testing for a Class A wiring scheme involved in the loops. By Class A operation is meant that there are two separate channels involved in each loop. A continuity test is sequentially performed on both channels of the loop such that discontinuities can be precisely located.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.