When you speak into a cell phone you sound waves must be converted into with each other wave form in order to transmit the signal

Radio waves. A cell phone transmits its signal to the towers by electromagnetic waves.

The electromagnetic waves are in the radiofrequency region of the electromagnetic spectrum.

Most cell phones in North America use radiofrequencies between 700 MHz and 850 MHz and between 1700 MHz and 2500 MHz.

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