GSM stands for Global System for Mobile communication, while CDMA stands for Code Division Multiple Access GSM uses FDMA (Frequency division multiple access) and TDMA (Time division multiple access). GSM supports transmitting data and voice both at once, but CDMA have not this feature.

The main distinction between GSM and CDMA is that in GSM, the customer information is put on a SIM card which can be moved to a new mobile phone. Whereas only mobile phones from a set of whitelisted companies can be used with a CDMA network. The call quality of both nationwide networks heavily depends on the network coverage. GSM users can experience better voice quality than CDMA users or vice versa in particular areas. Furthermore, the GSM network can transmit voice and data simultaneously. On the other hand, not all CDMA phones can transmit voice and data at the same time. In addition to the network congestion, CDMA call quality tends to be better than GSM.

At one corner, GSM operators say it is better “because it uses a SIM chip, it is the most used technology worldwide, it is more secure and it is more advanced”.