Burglar alarm system
United States Patent 2220427
Inventors:
Reinhold, Romanus Harald Anton
Publication Date:
11/05/1940
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Assignee:
ERICSSON TELEFON AB L M
Primary Class:
Other Classes:
340/507, 340/556, 250/221, 250/208.400, 367/93
International Classes:
G08B13/183; G08B13/18