发明授权
US5142571A Digital telephone set having an emergency switching function and
communication system having the same
失效
具有紧急切换功能的数字电话机和具有该紧急切换功能的通信系统
- 专利标题: Digital telephone set having an emergency switching function and communication system having the same
- 专利标题(中): 具有紧急切换功能的数字电话机和具有该紧急切换功能的通信系统
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申请号: US704858申请日: 1991-05-21
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公开(公告)号: US5142571A公开(公告)日: 1992-08-25
- 发明人: Yutaka Suzuki , Shigehiko Yazawa , Michihiro Hamada , Yoshiaki Inoue
- 申请人: Yutaka Suzuki , Shigehiko Yazawa , Michihiro Hamada , Yoshiaki Inoue
- 申请人地址: JPX Kawasaki
- 专利权人: Fujitsu Limited
- 当前专利权人: Fujitsu Limited
- 当前专利权人地址: JPX Kawasaki
- 优先权: JPX63-263634 19881019; JPX1-38773 19890217
- 主分类号: H04M1/253
- IPC分类号: H04M1/253 ; H04M3/12
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.
公开/授权文献
- US5795656A Thermal transfer sheet 公开/授权日:1998-08-18
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