CDMA2000 is a 3rd generation mobile communications standard within the IMT-2000 family. It evolved from the 2nd generation cdmaOne/IS-95 standard and is designed to offer improved data capabilities. CDMA2000 1X introduced packet data with peak bitrates of 144 kbps (upgradable to 307 kbps), while CDMA2000 1X-EV-DO supported data rates up to 2.4 Mbps on the downlink. The final phase, CDMA2000 1X-EV-DV, achieved even higher peak rates of 3.09 Mbps, simultaneous voice and high-speed data, and improved Quality of Service. CDMA2000 was developed by 3GPP2 and is part of the IMT-2000 standard family.