Title:
Electromagnetically operated polarized bell ringer
United States Patent 3116481


Inventors:
Walter, Kalin
Spencer, Robert A.
Application Number:
US7861460A
Publication Date:
12/31/1963
Filing Date:
12/27/1960
Assignee:
BELL TELEPHONE LABOR INC
Primary Class:
Other Classes:
335/230
International Classes:
G10K1/062; G10K1/063
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