Part of a family of cdma2000 1x digital wireless standards. 1xEV-DO is a "3G" standard. EV-DO stands for "EVolution, Data-Only".
1xEV-DO is based on a technology initially known as "HDR" (High Data Rate) or "HRPD" (High Rate Packet Data), developed by Qualcomm. The international standard is known as IS-856.
Unlike other "1x" standards, EV-DO only addresses data - not voice. It requires a dedicated slice of spectrum, separate from voice networks using standards such as 1xRTT.
1xEV-DO offers very high data rates - up to 2.4 mbps - averaging 300-600 kbps in the real world. This is much faster than the 50-80 kbps typically offered by 1xRTT technology.