SECURITY ALARM SYSTEM
United States Patent 3550111
US Patent References:
Bank holdup deterrent systems
- - 2909767
Signalling circuit
- - 2983912
Secure communication line
- - 3135951
Electrical protective system
- - 3174143
Electrical protection system
- - 3307176
Bank holdup deterrent systems
- - 2909767
Signalling circuit
- - 2983912
Secure communication line
- - 3135951
Electrical protective system
- - 3174143
Electrical protection system
- - 3307176
Inventors:
Ervin, Harold D.
Publication Date:
12/22/1970
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Export Citation:
Assignee:
Harold, Ervin D.
Primary Class:
Other Classes:
340/309.160, 340/501, 340/693.400, 340/535, 340/693.100, 340/521
International Classes:
G08B19/00; G08B19/00