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发明名称
Telephone-exchange system
摘要
申请公布号
US1795640(A)
申请公布日期
1931.03.10
申请号
US19280306812
申请日期
1928.09.19
申请人
BELL TELEPHONE LABORATORIES, INCORPORATED
发明人
COLLIS RAYMOND E.
分类号
H04M17/02
主分类号
H04M17/02
代理机构
代理人
主权项
地址
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