This thread has a lot of good and valid information. Please allow me to add some value (I hope):
VOICE/TEXT ONLY MOBILE PHONES:
As regards Verizon offered phones. until recently, the ONLY technology Verizon used was CDMA. That is the North American non-GSM, analog network Verizon was among the first to develop as cellular technology developed several decades ago. As the European and worldwide GSM technology spread across the oceans to North America, Verizon ensured customer "loyalty" by producing phones that worked ONLY on CDMA technology.
They even had Verizon-only models of popular Nokia, Samsung, LG, and Motorola handsets produced with only CDMA circuitry inside. As a general rule, CDMA-based phones did not have nor accept GSM SIM cards - until very recently. At the same time, their North American competitors, ATT, t-Mobile, Sprint, MCI, etc. ALL adopted the global standard - GSM technology.
Fast forward a decade or so. About 10 years ago, cellular service providers in North America only sold phones with strict contracts, expensive calling plans, and "locked" the phones so they would only work on their network - at least for a specified period. This happened even if you swapped the worldwide standard SIM card out for another SIM card, either in North America or abroad.
In North America, unlocked phones were not available at retail outlets until last past year or so. They are available now, but they are VERY expensive, and you have to ask specially for them. Conversely, in Europe, I believe it is unlawful to require someone to subscribe to your cellular service just to purchase a phone. So, most phones are sold unlocked.
However, more recently, after 90-days or so, most U.S. and Canadian carriers will provide an unlocking code to enter to unlock your phone, if you jump through the requisite hoops to ask them nicely. Once unlocked, your GSM capable phone can be used anywhere in the WORLD with the correct SIM, and...IF it has the correct frequency receiver/transmitter built in.
This last bit is the key issue for basic voice / text handsets. Basically voice/text only phones are sold as dual band, tri-band, or quad band models. Across the world, except for Japan, there are four (4) GSM frequencies used. In North America, GSM phones used the 850 Mhz and 1900 Mhz frequency bands. In the REST of THE WORLD (except Japan), GSM phones use the 900 Mhz and 1800 Mhz frequency bands. Japan uses a fifth, non-standard frequency.
So, as regards BASIC MOBILE or CELLULAR phones using GSM technology, to use a North American handset in Europe, it must have one or both of the European band frequencies and be unlocked so as to accept a European GSM card. My solution for the past 10-years or so has been to buy only quad-band phones using GSM technology. When I lived in Europe for several years, I picked up a pre-paid SIM card at my local Carrefour supermarket.That gave me a European phone number.
When I land in Europe from the U.S., I swap my U.S. t-mobile SIM card out for the European SIM card - instant brain transplant! My U.S. handset was now Belgian! My phone memory still has all my contact information. Only my texts are gone because they are stored on the SM card. I continue to maintain that SIM and Belgian phone number active and I use it all over the world. When I land in the U.S., I again swap the SIM back to my U.S. t-Mobile SIM
SMART PHONE and iPHONES:
Fast forward to - like now. Almost everyone (except Luddites like me) is using a Smart Phone of one make or another. With slight variation, they all have near identical frequency capabilities. You need to check the specifications closely before you buy. I believe they all accept either micro or nano-sized SIM cards, depending on make and model, to enable those handsets to communicate with systems worldwide.
EXCEPT that Verizon still locks it's smart phones to its proprietary CDMA-based technologies as the default for voice and text use. Even though the iPhone or other Smart Phones have a SIM tray for a micro or nano-sized SIM card supporting worldwide GSM frequencies, it WILL NOT WORK unless Verizon unlocks the SIM circuitry for foreign use. Check with them on doing this. Be prepared for push-back. They prefer you use their overseas services at extortionate per minute rates.
For all other brand North American-sourced Smart Phones including iPhones,
check your specifications. For the large tranche of you who use the iPhone, here is the technical specification web page for the UK iPhone 5S model.
http://www.apple.com/uk/iphone-5s/specs/
It should be the same as the continental model. Bear in mind the following:
- To use GSM VOICE capability in North America and all of Europe, any voice/text-only mobile phone (and all Smart Phones /iPhones) for use on the Camino must recognize the GSM/EDGE (850, 900, 1800, 1900 MHz) frequencies. The phone must be UNLOCKED to accept a foreign SIM card. and you have an active foreign SIM card. The bolded frequencies are Europe-specific, the plain face type is North American-specific
- To use older basic data services, any mobile phone must support the UMTS "bridge technology" that rode on the GSM standards BEFORE the 3G and 4G technologies were developed and promulgated. The basic, generic UMTS frequencies are listed as: UMTS/HSPA+/DC-HSDPA (850, 900, 1700/2100, 1900, 2100 MHz)
- To use 3G or 4G data services, your smart phone must recognize as many of the extant data frequencies as possible.
- Here is the Tech Specs page for the U.K. iPhone 5S (Model A-1453) specification - LTE (Bands 1, 2, 3, 4, 5, 8, 13, 17, 18, 19, 20, 25, 26).
- Here is the U.S. Tech Specs page for the iPhone 5S: http://www.apple.com/iphone-5s/specs/. NOTE: the same model A-1453 is sold in three or four variants.
- Lastly, here is the Tech Specs page for the Spanish iPhone 5S: http://www.apple.com/es/iphone-5s/specs/. NOTE: the same model A-1453 is sold in three or four variants.
- Based on the above matching specifications, and if one were inclined to buy an iPhone, my recommendation would be to buy the model A-1453 in the identical configuration as in the U.S., Canada, U.K., Spain (and presumably the rest of Europe). It should work everywhere.
If one were to purchase a Smart Phone matching these technical specifications, as regards frequencies supported, you should be able to use an appropriate SIM card (micro or nano-sized) from any country in the world - PROVIDED - that your phone is unlocked from your home service provider. Check with your provider for how to accomplish this.
In North America; bands 4, 7, 12, 13, 17, 25, 26, and 41 are used on the 700, 800, 1900, 1700/2100 (AWS) and 2600 MHz frequencies are used. Whereas, in Europe; bands 3, 7, and 20 are used on the 800, 900, 1800, 2600 MHz frequencies are used. As you can see, there is NO COMMONALITY as to bands or frequencies used, except at the band 7 / 800 Mhz overlap. So, you need to be careful when buying any Smart phone to choose a model that has as much built in flexibility as possible for your intended use.
I know is sounds confusing, but I hope it helps people avoid making expensive mistakes.
Happy New Year to all!