Patent search ap:("BELL TELEPHONE LABOR INC") AND inv:"KEEFER FRANK D" Page 1

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发明授权
Multistage end marked folded ferreed switching network 失效
Title translation: 多级终端标记的FERREED切换网络

公开(公告)号：US3515810A

公开(公告)日：1970-06-02

申请号：US3515810D

申请日：1967-01-05

Applicant: BELL TELEPHONE LABOR INC

Inventor： KEEFER FRANK D , THELEMAQUE LOUIS E , WALSH HENRY J

IPC: H03K17/80 , H03K17/81 , H04Q3/00 , H04Q3/42

CPC classification number: H03K17/81 , H03K17/80 , H04Q3/0012

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