Part of a family of CDMA2000 1x digital wireless standards. 1xEV-DO (EVDO) is a "3G" CDMA standard. EVDO originally stood for "EVolution, Data-Only", but recently is also referred to as "EVolution, Data-Optimized".
EVDO provides data rates over 10 times faster than 1xRTT, the previous data technology for CDMA networks.
Unlike some other "1x" standards, EVDO only addresses data - not voice. It requires a dedicated slice of spectrum, separate from voice networks using standards such as 1xRTT.
There are currently two main versions of EVDO: "Release 0" and "Revision A".
Release 0 (r0) is the original version, and the first to be widely deployed. Rel. 0 offers 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.
Revision A (rA) integrates most of the faster data technology originally designed for the 1xEV-DV Revision D standard, and improves latency. These enhancements allow features such as VoIP and video calling. The downlink (download) theoretical peak data rate compared to Release 0 is improved from 2.4 mbps to 3.1 mbps.
In terms of data speed and general technology evolution, the closest equivalent to EVDO for GSM/WCDMA networks would be HSDPA.
EVDO 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.