发明名称 |
Key telephone system |
摘要 |
A key telephone system, in which a plurality of key telephone sets are selectively connected to a plurality of CO lines by the use of a plurality of talking lines under control of a key service unit and a plurality of control lines. In order to seize a CO line, a CO line seizure signal from one of key telephone sets is time-divisionally transmitted at a low speed and received by a speed change memory of the key service unit. A high-speed output from the speed change memory is added with dial or hook information and then space-divided for seizing a desired one of the CO lines. A talking operation, a holding operation, a privacy operation and a synchronizing operation in this system are performed on the base of the above operation principle.
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申请公布号 |
US4234765(A) |
申请公布日期 |
1980.11.18 |
申请号 |
US19780917578 |
申请日期 |
1978.06.21 |
申请人 |
IWASAKI TSUSHINKI KABUSHIKI KAISHA |
发明人 |
SEKIGUCHI, KOUICHI;TAKEMATSU, HIKARU;KATSUKURA, KAZUTADA |
分类号 |
H04M9/00;(IPC1-7):H04Q5/18 |
主分类号 |
H04M9/00 |
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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