GSM vs. CDMA

It occurred to my after yesterday's post that I should mention something about the difference between GSM and CDMA as that is an important driver in the decision on which wireless carrier to use. I'll keep this short as it is a complex topic, but aside from compatibility issues (GSM is common in Europe, CDMA in Asia, the U.S. is mixed) there's a functional difference for smartphone users. Most CDMA devices are not able to use their high-speed data network (EVDO) while talking on the phone. The GSM devices with HSDPA permit data and voice as long as the device is on the high-speed network. So if you're frequently phoning a friend while looking up cache information, look for a 3G GSM carrier (AT&T or T-Mobile in the U.S.). If you're not concerned about concurrent data and voice, look at the CDMA carriers (Sprint and Verizon in the U.S.) as they tend to have better connection quality than does GSM. I tend not to be talking and using data but after having the luxury of using both at the same time it will be hard to go back to just one or the other.