Ever walk into a Verizon store with your AT&T phone? Not a lot you can do with it, is there? What about going into a Sprint store? Ever tried using T-Mobile’s data network if you don’t have a T-Mobile phone?
It’s a mess, and it’s unique to the USA. Almost every other country that has cell phone technology uses one standard system. If you’re in France, take your French cell phone to another provider and boom, you’re in business. New Zealanders have their choice of carriers without throwing away a perfectly good phone. Even in the “third world” it’s not a problem, although carrier choice may be limited.
So why is it that you can’t get a universal cell phone here in the US?
Part of it is the technology. AT&T and T-Mobile use the GSM system favored by Europeans. It works with smaller towers that must be spaced closer together to work. Here in the US, that system has a bad rap because it doesn’t work well in rural areas and AT&T has been slow to put up enough towers in cell-heavy cities like New York. Verizon uses the CDMA system favored by Southeast Asians. CDMA uses big, powerful towers but fewer of them. It generally results in fewer dropped calls in the US but the towers themselves are huge. If you see a large tower by the side of a highway, it’s big because it covers CDMA. Sprint, on the other hand, uses a mix of technologies that almost no one uses anymore. It’s finally shedding the iDEN system used by old chirpy Nextel phones but is still hanging onto the TDMA system used by AT&T in the early 2000s.
For data, it gets more confusing. Because data on cell phones has evolved so rapidly, there need to be 4 or 5 different systems in the average smartphone just to cover one carrier.
Another big part is the way the wireless licenses have been handed out. Strict FCC rules, combined by the large number of TV and radio licenses available in the US, have meant that cell service has to use little slices of the wireless spectrum so small that carriers can’t share them. So, each cell phone provider has several frequencies for voice and several more for data. (Curious? Check out this article.) If a phone were just designed to work with AT&T and Verizon, that phone would need 6 different radio transmitters just for the most common voice and data options. That uses a lot of power and takes up a lot of space.
There are some phones that will work on multiple carriers, but precious few. Some smartphones, including some Verizon iPhones and Galaxy phones can be moved to AT&T if they are unlocked. Unlocking is a process where the software installed by the carrier is removed. It’s legal and you can request it. But really if you’re changing carriers you should probably think about changing phones as well, as each carrier has a few extra frequencies used for high-speed data that the others do not have.