发明名称 |
Confirmation circuit for a two-way communication system |
摘要 |
A two-tone decoder decodes simultaneously at least two calling tones each having different frequencies coupled from a calling station to a called station and produces a first control signal upon cessation of the two calling tones. A timer responding to the first control signals produces a second control signal in the form of a pulse having a predetermined duration. A relay is activated by the second control signal and couples a confirmation tone to the calling station from a confirmation tone generator in the called station for the predetermined duration of the second control signal.
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申请公布号 |
US4092597(A) |
申请公布日期 |
1978.05.30 |
申请号 |
US19760713303 |
申请日期 |
1976.08.10 |
申请人 |
INTERNATIONAL TELEPHONE & TELEGRAPH CORPORATION |
发明人 |
PLACE, HARRY |
分类号 |
H04W88/02;(IPC1-7):H04B7/00 |
主分类号 |
H04W88/02 |
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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