Basic communication theory requires that a minimum sampling rate of twice the frequency of the signal to be sampled will result in an accurate representation of the original signal. Because the human voice does not exceed 4000 Hz, a sampling rate of 8000 samples per second, or once every 125 microseconds, is used.

The conversion process begins by analyzing each sample and converting it into an 8-bit word also called an octet. If there are 8 bits per sample and 8000 samples per second, then the product is 64,000 bits per second (64 kbps)—the digital voice channel.