Patent search ap:("BELL TELEPHONE LABOR INC") AND inv:"KOPP OTTMAN H" Page 1

1.

发明授权
Telephone system 失效

公开(公告)号：US2261370A

公开(公告)日：1941-11-04

申请号：US33524140

申请日：1940-05-15

Applicant: BELL TELEPHONE LABOR INC

Inventor： HERSEY RALPH E , KOPP OTTMAN H , NEWSOM JAMES B

IPC: H04M3/60 , H04Q3/00

CPC classification number: H04Q3/00 , H04M3/60 , H04Q3/0004

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