发明名称 |
ON-HOOK CUSTOMER PREMISE EQUIPMENT ALERTING SIGNAL DETECTION |
摘要 |
An apparatus for detecting customer premise equipment alerting signals (CAS) in a first telephone having a transmit circuit and a receive circuit and a hybrid line termination for connecting the transmit circuit and the receive circuit to a central office line, The apparatus includes an off-hook detector for producing an off-hook signal identifying whether or not the first telephone is in an off-hook state, an extension-in-use detector for producing an extension-in-use signal identifying whether or not a second telephone connected to the central office line is in an off-hook state, a CAS detector selectively operable to receive the CAS signals directly from the central office line and from the hybrid line termination and a control element for controlling the CAS detector in response to the off-hook signal and the extension-in-use signal. The control element acts to enable the CAS detector to monitor the CAS signals on the central office line directly when the second telephone is in the off-hook state and enable the CAS detector to monitor the CAS signals from the hybrid line termination when the first telephone is in an on-hook state, and the second telephone is in an off-hook state.
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申请公布号 |
CA2221504(A1) |
申请公布日期 |
1998.09.27 |
申请号 |
CA19972221504 |
申请日期 |
1997.11.19 |
申请人 |
NORTHERN TELECOM LIMITED |
发明人 |
KOS, STEPHEN;MCKINNEY, BRIAN CLIFFORD |
分类号 |
H04M1/57;H04M1/82;(IPC1-7):H04M3/22 |
主分类号 |
H04M1/57 |
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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