Alarm system including remote signalling means
US4064508A · kind A · utility
Assignees
Inventor
Key dates
| Filing date | Aug 9, 1976 |
| Grant date | Dec 20, 1977 |
| Priority date | — |
| Expiry date | Aug 9, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B27/00
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An improved alarm system is disclosed which includes one or more remote stations. Each remote station is connected to the central or control station by only three conductors or leads. The control and remote stations each include a pair of back-to-back LED diodes, the diodes of each pair emitting a different color light when current flows therethrough. The control and remote stations each also includes a key switch which is operative to "enable" and "disable" the alarm circuitry at the control station. By controlling the direction as well as the wave shape of the currents passing through the LED diodes, five different visual signals may be provided at the control and remote stations to indicate the status of the alarm system. Actuation of any of the key switches reverses the current through the LED diodes so that the different colors are indicated when the alarm system is "enabled" or "disabled". Pulsing means is provided at the control station for producing either a constant current through the LED diodes when an alarm condition of an instant loop does not exist and when a delay loop is open, and a pulsed current when an alarm condition in the instant loop is generated. The current…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.