It's my understanding that GSM and CDMA are incompatible with each other. Am I incorrect in this? Is it merely that phone carriers restrict at the device level? I'm not entirely convinced. I've heard of so called world phones which have the ability to communicate on either technology but that is not the same as saying that a GSM phone can operate on CDMA and vice versa.
Anyone care to further clarify?
**Edit **
-- my original statement spoke of frequency differences where I assumed that CDMA and GSM worked on different frequencies (though I didn't name technologies), This may well be an incorrect assumption on my part, i'll investigate and update.
**Update **
-- CDMA and GSM are the encoding methods/protocols used on cellular signals, not the signals themselves, so my understanding on that is clarified.
Giz Explains: What's the Difference between GSM and CDMA? - Gizmodo Here is a helpful link with additional information.