Speaker supervision in a public address system
US3989908A · kind A · utility
23Cited by
5References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 26, 1975 |
| Grant date | Nov 2, 1976 |
| Priority date | — |
| Expiry date | Jun 26, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R27/00
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Apparatus and technique for supervising a public address system such that any faults on the lines connected to speakers in the system or any faults within the speaker structures can be detected and suitable corrective action can be taken. To accomplish this purpose, only three wires or lines need be taken or extended to each zone within the public address system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.