We bandy about acronyms like EDGE, GSM, and EV-DO all the time when talking about cellphones and smartphones. We like to pride ourselves on the ability to explain what we're talking about concisely for the newcomer while not going too slow for the veteran. Nevertheless, sometimes a UMTS slips by without explanation. Here's a primer:
Focusing on what's relevant to today's smartphone buyer, both GSM and CDMA have two tiers of data networks. Older, slower standards are EDGE on the GSM side, and 1xRTT on the CDMA side. Both give you average data speeds in the 100 Kbps range, or about twice that of a dial-up modem. The newer, 3G wireless data technologies consist of UMTS and its HSDPA extension for GSM networks, and EV-DO Rev 0 for CDMA networks. These allow for much faster transfer speeds, averaging 300 Kbps for UMTS and 500 to 800 Kbps for EV-DO and HSDPA, or about that of a lower-cost DSL connection.
Acronyms Defined [Omnicellonline]
3G Glossary [CNET]