| 摘要 |
For use with a telecommunications network, circuit for, and method of, detecting telephone line status and a telephone instrument embodying the same. The circuit includes: (1) a high-impedance amplifier, couplable to the telecommunications network, for providing DC voltage representing a differential line voltage between tip and ring conductors of the telecommunications network and (2) a pulse-generation circuit, coupled to an output of the amplifier, for generating a signal having first and second states, the signal assuming the second state for a period of time inversely proportional to the differential line voltage between the tip and ring conductors.
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