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公开(公告)号:US3122612A
公开(公告)日:1964-02-25
申请号:US7407860
申请日:1960-12-06
Applicant: BELL TELEPHONE LABOR INC
Inventor: JOSEPH MICHAL , RIPPERE ROBERT O
IPC: H04Q3/62
CPC classification number: H04Q3/625
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2.Special trunk circuits for transmitting tones to calling subscribers 失效
Title translation: 用于向主叫用户发送音调的特殊中继电路公开(公告)号:US2591580A
公开(公告)日:1952-04-01
申请号:US5738248
申请日:1948-10-29
Applicant: BELL TELEPHONE LABOR INC
Inventor: JOSEPH MICHAL
IPC: H04Q3/00
CPC classification number: H04Q3/00
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公开(公告)号:US2722675A
公开(公告)日:1955-11-01
申请号:US34253853
申请日:1953-03-16
Applicant: BELL TELEPHONE LABOR INC
Inventor: JOSEPH MICHAL , STAEHLER ROBERT E
IPC: H04Q3/42
CPC classification number: H04Q3/42
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公开(公告)号:US2591579A
公开(公告)日:1952-04-01
申请号:US5738148
申请日:1948-10-29
Applicant: BELL TELEPHONE LABOR INC
Inventor: JOSEPH MICHAL
IPC: H04M3/14
CPC classification number: H04M3/14
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