Thursday, August 18, 2011

Dialtone Generation

In my last telephone set post I described what happens when a telephone handset is picked up. Here's a diagram showing that process.
Dialtone Generation

Dialtone is a signal formed by the simultaneous transmission of a 330 Hz tone and a 440 Hz tone. After the first number is dialed by the caller the dial-tone generator is shut off. 

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