Enhanced Data rates for GSM Evolution (EDGE) was originally released in 2003 by the Global mobile Suppliers Association (GSA) as a new protocol that would allow enhanced data communication through multiple packet switching. The EDGE network was first released in the United States by major carrier T-Mobile for their data handsets such as the Blackberry and T-Mobile Dash. Essentially EDGE is as fast as 3G networks, but is widely considered 2.5G in terms of speed.
There are approximately 170 networks across the United States that are capable of supporting the duplex packet switching involved in EDGE communications. Not all devices (cellular phones) are capable of operating on a International Mobile Telecommunications-2000 (IMT-2000) network, otherwise known as 3G. You need to first check that your phone is capable of operating on a 3G. The best place to check is by removing the battery and looking in the battery slot on the handset for any of these: GSM EDGE, UMTS, CDMA2000, DECT and WiMAX. If your phone is compatible with any of these protocols, you only need contact your current provider, or the new provider you are looking at in order to purchase a 3G data plan.
It should be noted that 3G and EDGE networks are owned and operated by major phone carriers and involve massive amounts of proprietary software and hardware in order to operate. The end user may only interact with these networks according to their respective licensing agreements.
The actual technology involved between a 3G network and a EDGE or enhanced EDGE network is dissimilar; different hardware, different software and different digital/analog signal. While 3G networks are considered broadband, having up to 14.4 megabytes per second Mb/s of transfer, they have a much higher degree of latency. Latency means that a significant portion of your data which is broken down into packets gets lost when transferring between your handset and the cellular relay tower. AT&T chose to support the EDGE network with their Apple iPhone because it uses considerably less power (increasing battery life) as well as the fact that EDGE uses a packet checking scheme to ensure minimal latency. The iPhone then uses wireless hotspots (Wi-Fi) in order to increase its download speed when using intensive applications that require the additional bandwidth. The enhanced EDGE networks in place by both AT&T and T-Mobile allow approximately 0.5 Mb/s of transfer in most major cities.