公开(公告)号：US5142571A

公开(公告)日：1992-08-25

申请号：US704858

申请日：1991-05-21

申请人： Yutaka Suzuki ,  Shigehiko Yazawa ,  Michihiro Hamada ,  Yoshiaki Inoue

发明人： Yutaka Suzuki ,  Shigehiko Yazawa ,  Michihiro Hamada ,  Yoshiaki Inoue

IPC分类号： H04M1/253 ,  H04M3/12

CPC分类号： H04M3/12 ,  H04M1/253

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.

摘要翻译： 数字电话机包括数字电话电路和紧急模拟电路。 通常，数字电话电路被激活，使得与其共同提供的手机连接到数字传输线。 在紧急情况下，紧急模拟电路被激活而不是数字电话电路，使得手机连接到模拟传输线。 拨号键盘单元和扬声器与数字电话电路和紧急模拟电路共同提供。