发明名称 |
TELEPHONE LINE TEST SET WITH A SPEAKERPHONE FOR COMMUNICATIONS |
摘要 |
A telephone test set that performs dry loop testing of telephone lines has a passive speech network, a speakerphone circuit, and an amplifier and a speaker coupled to the speakerphone circuit. The passive speech network and the speakerphone circuit area isolated by the use of latching relays which are switched by a relay driver circuit that provides a short current burst. Line power can be used to power the speakerphone, so as to extend battery life of a battery which can augment the line power as needed. |
申请公布号 |
EP0558737(B1) |
申请公布日期 |
1999.11.17 |
申请号 |
EP19920920843 |
申请日期 |
1992.09.18 |
申请人 |
HARRIS CORPORATION |
发明人 |
PARKER, GEOFFREY, H.;HEFLEY, ANDREW, J. |
分类号 |
H04M1/24;H04M1/60;H04M3/30 |
主分类号 |
H04M1/24 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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