Title:
Telephone apparatus for the deaf
United States Patent 1343717


Inventors:
Hanson, Earl C.
Application Number:
US30328519A
Publication Date:
06/15/1920
Filing Date:
06/11/1919
Assignee:
Hanson, Earl C.
Primary Class:
Other Classes:
381/313, 381/319
International Classes:
H04R25/04
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