发明名称 |
Digital telephone set having an emergency switching function and communication system having the same |
摘要 |
A digital telephone set includes a digital telephone circuit and an emergency analog circuit. Normally, the digital telephone circuit is made active so that a handset provided in common therewith is connected to a digital transmission line. In an emergency, the emergency analog circuit is made active instead of the digital telephone circuit so that the handset is connected to an analog transmission line. A dial key pad unit and a speaker are provided in common with the digital telephone circuit and the emergency analog circuit.
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申请公布号 |
US5142571(A) |
申请公布日期 |
1992.08.25 |
申请号 |
US19910704858 |
申请日期 |
1991.05.21 |
申请人 |
FUJITSU LIMITED |
发明人 |
SUZUKI, YUTAKA;YAZAWA, SHIGEHIKO;HAMADA, MICHIHIRO;INOUE, YOSHIAKI |
分类号 |
H04M1/253;H04M3/12 |
主分类号 |
H04M1/253 |
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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