EVDO, also known as EV-DO, 1xEvDO and 1xEV-DO, is a standard for high speed wireless broadband. The acronym is short for "Evolution, Data Only" or "Evolution, Data Optimized". The official name, defined by the Telecommunication Industry Association, is "CDMA2000, High Rate Packet Data Air Interface". It is one of two major Third Generation, or 3G, wireless standards. The competing standard is known as W-CDMA.

3G is designed to provide voice and high-speed mobile data using the cellular approach already proven to work in mobile phone networks. The biggest obstacle to implementing high speed wireless networks is the lack of bandwidth, or range of usable frequencies. Just as only so many radio stations can be squeezed onto the FM dial, only so much data can be transmitted across the available bandwidth. EVDO is an advanced CDMA technology developed by Qualcomm to deal with this limitation.

CDMA, Code Division Multiple Access, uses advanced mathematical techniques to allow multiple wireless devices to transmit simultaneously on the same frequency. Every device, such as a cell phone, is assigned a unique mathematical signature. It applies this signature to the original signal and transmits the modified signal. A receiver applies the inverse of the mathematical operation to recover the original signal.

Traditional wireless networks create a physical path between receiving and sending devices, much like traditional telephone networks. EVDO instead adopts the same approach used for the internet. IP, the Internet Protocol, breaks data into small pieces called packets. Each packet is sent independently of all the other packets. This saves bandwidth for use by other devices; when neither party on a phone call is speaking, the connection consumes no bandwidth because there are no packets to send. Or, when an internet web site is accessed, no bandwidth is used until the site starts sending the web page.

EVDO has a theoretical throughput of 2.4 megabits per second. This is as fast as many residential DSL and cable broadband connections currently available in the United States. Qualcomm has produced impressive demonstrations of EVDO's capabilities; in one, a video conference was conducted with a participant traveling in a car at 60 miles per hour (96 km/hour). In another demonstration, a phone call was placed from a bullet train moving in excess of 150 miles per hour (240 km/hour).

A significant advantage of EVDO over competing technologies is that it uses the same broadcasting frequencies as existing CDMA networks. As purchasing spectrum from regulatory agencies is extremely expensive, this brings down the cost of building and using the new networks. The major EVDO deployments in the US are by Verizon and Sprint, and there is also a large network in Korea. At present, EVDO has not made significant impact in Europe or other major Asian markets; W-CDMA is the 3G standard of choice in those regions.