EP 0484880 A3 19930811 - RADIO ALARM SYSTEM
Title (en)
RADIO ALARM SYSTEM
Publication
Application
Priority
DE 4035070 A 19901105
Abstract (en)
[origin: EP0484880A2] A radio alarm system is described which offers adequate protection against interference due to blocking of the radio paths and against external manipulation. For this purpose, it is proposed that each signalling unit of the alarm system transmits at least two radio signals for an alarm signal, using a different carrier frequency and being coded in identical or different fashion. The central unit accordingly receives with its receivers the at least two radio signals from each signalling unit and checks the affiliation of the signalling units transmitting the radio signals by checking the validity of the coding. It is proposed in addition that an evaluation unit be provided in the receiver unit of the central unit which identifies the field strength of each received radio signal, analyses the associated data telegrams for affiliation to the system of the signalling units transmitting them, if an invalid data telegram is detected, compares the value of the received field strength of the radio signal concerned with a predefinable minimum value and, if this minimum value is exceeded by a predefinable amount, where this amount must be exceeded for a specific time period, triggers a warning indicator. <IMAGE>
IPC 1-7
IPC 8 full level
G08B 25/10 (2006.01); G08B 26/00 (2006.01); G08B 29/16 (2006.01); H04B 7/12 (2006.01)
CPC (source: EP)
G08B 25/10 (2013.01); G08B 26/007 (2013.01); G08B 29/16 (2013.01)
Citation (search report)
- [YD] US 4511887 A 19850416 - FIORE LOUIS T [US]
- [Y] FR 2502817 A1 19821001 - MERE MALLERAY ET CIE [FR]
- [YD] US 4603325 A 19860729 - MARINO FRANCIS C [US], et al
- [A] PATENT ABSTRACTS OF JAPAN vol. 5, no. 99 (E-63)(771) 26. Juni 1981 & JP-A-56 42 448 ( MATSUSHITA ) 20. April 1981
Designated contracting state (EPC)
AT BE CH DE ES FR GB IT LI LU NL
DOCDB simple family (publication)
EP 0484880 A2 19920513; EP 0484880 A3 19930811; EP 0484880 B1 19970226; AT E149262 T1 19970315; DE 4035070 A1 19920507; DE 4035070 C2 19930415; DE 59108569 D1 19970403
DOCDB simple family (application)
EP 91118836 A 19911105; AT 91118836 T 19911105; DE 4035070 A 19901105; DE 59108569 T 19911105