Time-Division Multiple Access (TDMA) and Code-Division Multiple Access (CDMA) are the two basic digital systems used in cell phones. TDMA provides that multiple users are separated in time and each user is given a short time slot to handle part of his conversation. CDMA is considered the superior digital technology between the two because it separates the channels by giving each user a unique code used to identify his/her conversation and generally has better performance than TDMA.

CDMA has been in use for sometime now by the military for communication, radar and sonar secrecy and anti-jamming. The best example of this is the Global Positioning System or GPS which is the military satellite navigation that has displaced almost every other method of navigation for military and civilian users.