CDMA:

 CDMA (Code Division Multiple Access) - also known as spread spectrum - is a cellular phone technology that transmits voice and data signals over a shared portion of the spectrum. Invented by Qualcomm  and supported by MCI Communications, CDMA is marketed as less costly to implement than the GSM and TDMA cellular phone systems. It operates in both the 800 MHz (cellular) and 1.9 GHz (PCS, or Personal Communications Services) bands.

 CDMA networks are upgrades to currently existing analog systems and are used by a large number of the North American telecom carriers, including AT&T, Bell Atlantic, GTE Corp., Ameritech, and Northern Telecom. CDMA's main rival is GSM, Europe's cellular technology.