Verizon 4G Phones, AT&T LTE Network Don't Mix

Right now there are four networks in the United States and moving phones between the networks is either very limiting or simply not possible. The theory was that once everyone moved to Long Term Evolution networks, our cellular systems would work a bit more like they do in Europe, where any phone will work on any network as long as you have a SIM card from the carrier.

The carrier market in the United States is very complex compared to Europe. There, everyone is on a GSM system and they all use one of a few frequencies. Every phone there will work on all of the networks as long as the phone has a quad-band radio. The only problem you'd have is when trying to use some of the high-speed features in some areas.

Here, it is a mess by comparison. Only AT&T and T-Mobile use GSM, and even these two use different frequencies. AT&T has stuck with frequencies that are more common around the world, which means an AT&T phone will be your best bet when traveling abroad. While AT&T uses the more common 850-MHz and 1900-MHz bands, T-Mobile uses 1900 MHz for 2G and 1700 MHz/2100 MHz for 3G. That means if you are on AT&T or T-Mobile and swap to the other network, the 1900-MHz commonality will allow voice to work, as well as 2G data. But 3G is out of the question. This is why once the iPhone 3G came out, jailbreaking it to run on T-Mobile lost much of its luster.

For Sprint and Verizon, it gets worse. Those two use CDMA networks and there are no SIM cards to swap. You have to have the carrier activate a phone for you, and if it isn't their phone, you won't have much success.

LTE phones though, regardless of the network, use SIM cards and LTE technology. These so-called 4G phones are supposed to do away with much of the confusion here in the United States. There are people in business that are waiting for all of the networks to have 4G capabilities. This would allow employees to swap SIM cards when traveling in remote areas where the primary carrier of choice may not have coverage, and it would certainly improve the global travel situation.

Verizon though, doesn't use the same frequencies for LTE that AT&T does, according to Sascha Segan. That means we are right back where we started.

Those of us in the United States, though, shouldn't feel too bad. Our European cousins may be in for similar problems. There are 12 approved frequencies for LTE use there.