Title:
Sound recording and reproducing system
United States Patent 2114471
Inventors:
Keller, Arthur C.
Mount, Vernon
Rafuse, Irad S.
Publication Date:
04/19/1938
Assignee:
BELL TELEPHONE LABOR INC
Other Classes:
369/91, 369/132, 369/136
International Classes:
H04R9/16; H04R11/12; H04R9/00; H04R11/00