Control circuits
United States Patent 2535661
US Patent References:
Telephone control circuit
- - 2112366
Telephone system
- - 2283395
Automatic toll ticketing system
- - 2342279
Telephone control circuit
- - 2112366
Telephone system
- - 2283395
Automatic toll ticketing system
- - 2342279
Inventors:
Adam Jr., Armand O.
Avery, Robert C.
Avery, Robert C.
Publication Date:
12/26/1950
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Export Citation:
Assignee:
BELL TELEPHONE LABOR INC
Primary Class:
Other Classes:
379/246, 379/288
International Classes:
H04Q3/00