GSM and CDMA are the two main digital mobile technologies. CDMA uses direct sequence spread spectrum technology and allows multiple users to access the network using the same frequency band at the same time through the use of unique codes. In CDMA, users share the same bandwidth and are separated by codes rather than frequency or time slots. CDMA provides advantages like better voice quality and easier frequency planning compared to TDMA/FDMA systems. GSM uses TDMA and FDMA to allow multiple access through allocating users to different time slots and frequency channels.