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Consumer Electronics by S. P. Bali

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FEATURE PHONES AND ANSWERING MACHINES

When additional features have been added to the basic single-line telephone, such as last number redial, the phone is called a feature phone. The feature phone has a microprocessor and memory contained in the telephone but is still powered by the standard 52 V dc voltage from the central exchange. This electronic phone can be designed to include special features such as an answering machine. The answering machine uses an electronic solid state ring detector, which signals the microprocessor on each ring received. The microprocessor will count the number of rings received and can be programmed to answer on two or four rings, or not answer at all. The answering machine also includes a DTMF (Dual Tone Multi ...

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