发明名称 Loop current detector with threshold setting impedance
摘要 In a loop circuit closure detector, a circuit which connects a voltage comparator to the loop circuit is biased so that the comparator indicates loop circuit closure at a predetermined minimum non-zero value of loop current. Comparator inputs are both coupled to supply voltage connections by approximately equal-attenuation paths and are both coupled to said loop circuit by approximately equal-attenuation paths.
申请公布号 US4454477(A) 申请公布日期 1984.06.12
申请号 US19820372741 申请日期 1982.04.28
申请人 AT&T BELL LABORATORIES 发明人 JOFFE, DANIEL M.
分类号 H04M3/22;H04Q1/38;H04Q3/00;(IPC1-7):H04M3/22 主分类号 H04M3/22
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