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公开(公告)号:US1738245A
公开(公告)日:1929-12-03
申请号:US31643228
申请日:1928-11-01
Applicant: BELL TELEPHONE LABOR INC
Inventor: HINRICHSEN EDWARD E
IPC: H04Q3/62
CPC classification number: H04Q3/625
公开(公告)号:US1738245A
公开(公告)日:1929-12-03
申请号:US31643228
申请日:1928-11-01
Applicant: BELL TELEPHONE LABOR INC
Inventor: HINRICHSEN EDWARD E
IPC: H04Q3/62
CPC classification number: H04Q3/625