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1.Monitoring device for distinguishing between voice and data signals 失效
Title translation: 监控语音和数据信号之间的差异监测设备公开(公告)号:US3448215A
公开(公告)日:1969-06-03
申请号:US3448215D
申请日:1966-08-22
Applicant: NORTHROP CORP
Inventor: ENGEL JOEL E
CPC classification number: H04L43/00