Digital transmission apparatus particularly adapted for security systems
US4191948A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 23, 1978 |
| Grant date | Mar 4, 1980 |
| Priority date | — |
| Expiry date | Oct 23, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B25/10
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A digital transmission system comprises a transmitter and a receiver for use in a security system. An alarm code is set by means of switches in both the transmitter and receiver and is indicative of the address or location of a monitored location. The location as monitored contains a sensor which is in either an opened or a closed condition indicative of a secure or unsecure status. The transmitter operates to transmit a digital code for each change in the status of the loop. The code contains bits which define the alarm code or address, while additional bits define the loop status as opened or closed in conjunction with the condition of a battery which is used to power the transmitter. The receiver is adapted to receive the transmitted signal and is operative to compare the transmitted address with the code stored or programmed by the receiver switches. If a valid code is received within a predetermined interval, the receiver operates to decode the loop status by means of an updown counter. If the loop has been opened and closed the same number of times, the updown counter will indicate a secure position at the end of the day. The receiver also contains circuitry to monitor the ba…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.