CDMA – Code Division Multiple Access
Since there’s only a limited number of frequencies for wireless devices to communicate on, they must somehow share this space. CDMA, divides this space up between devices by assigned Walsh Codes. These codes, applied to the transmissions with other algorithms, ensure that the transmissions arrive at their target destination, and only their target destination.
Without knowing the Walsh Code, and other information like the ESN, anyone listening on the frequency will only hear noise. But someone with the rights codes and algorithms can listen and pick out a signal. CDMA is very secure, and works well when there’s lots of interference.