发明名称 |
Apparatus and method for incoming call detection and alarm circuitry for cellular telephones |
摘要 |
An apparatus for use with a cellular telephone to indicate an incoming telephone call to a user includes a cellular telephone battery pack has a circuit that generates a voltage signal with a value representative of the current being drawn from the battery by the operation of the cellular telephone. A status determination circuit monitors the voltage signal and generates a waiting for call state signal whenever the value of the voltage signal decreases from a first selected higher value to a first selected lower value for a first preselected period of time. An incoming call detection circuit whenever the waiting for call state signal is present and either the voltage signal increases from a second selected lower value to a second selected higher value and remains at or above the second selected higher value for a second preselected period of time, or the current goes from a lower preselected current value to a higher preselected current value and remains at or above the higher current value for a third preselected period of time. An alarm is operative upon receipt of the alarm start signal for indicating an incoming call to a user. Also a cutoff circuit monitors the voltage of the battery and disables the apparatus further operation whenever the battery voltage drops below a preselected cutoff value to avoid damage to the battery.
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申请公布号 |
US5640441(A) |
申请公布日期 |
1997.06.17 |
申请号 |
US19950437173 |
申请日期 |
1995.05.08 |
申请人 |
ORAELECTRONICS, INC. |
发明人 |
SERRANO, ARTHUR;AVITAN, ASHER |
分类号 |
H04M19/04;(IPC1-7):H04M1/24;H04M1/00;H04M3/22;H04M9/00 |
主分类号 |
H04M19/04 |
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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