How do I know if my US phone will work overseas?
I have a smartphone bought in the US through a US carrier, not rooted or otherwise modified. I understand that some phones will work overseas, some won't, and some can if I make modifications to the phone. How do I figure out if any given phone will work in any given country?
I imagine that the factors include hardware (specific phone, network technology), who my carrier is, and exactly where I'm going. I'm not asking about costs; I understand that overseas use might be expensive and I would have to check with my carrier and my specific plan. I'm asking how to know, before going, if I'll be able to make calls and use data at all (other than through local wireless networks).
I'm trying to ask this question generally, rather than about one particular phone that will make the question obsolete in a year.
Best Answer
I understand you intend to use your phone with the original network provisioning of your operator (e.g. the original SIM card); if so, the question has two parts to it:
is the phone physically capable of connecting to a foreign network?
- is the foreign network technology (e.g. GSM, UMTS, LTE, or sometimes cdmaOne/CDMA2000) supported by your phone?
- are the frequencies for a given technology match?
is an agreement in place between your operator and the foreign operator, and whether it covers the technology and frequency combinations that you phone supports?
The network technology
Some technologies are backwards compatible with others, whereas others are incompatible with each other. The compatibility is denoted by a technology family of a single generation, and the frequency over which it is used.
For example, most people don't realise that phones that only support GSM are incompatible with UMTS/HSPA-only networks, which do exist.
You need to figure out the technologies that your phone supports, and jot down the bands for each technology.
This is a list of some common standards, and some substandards that are all backwards compatible within each other:
- GSM: GRPS, EDGE.
- Popular GSM frequencies are 850MHz, 900MHz, 1800MHz and 1900MHz.
- UMTS: W-CDMA, HSPA, HSDPA, HSUPA, HSPA+ etc.
- Popular UMTS frequencies are 850MHz, 900MHz, 1700/2100MHz (that's a single frequency, called AWS), 1900MHz, 2100MHz (not to be confused with 1700/2100MHz, which is a separate, and incompatible, frequency).
- LTE.
- It has so many slightly-different bands, that it became meaningless to use the MHz notation for each frequency, and most frequencies are referred to through some synthetic numbers from the LTE family of standards. Unlike GSM and UMTS, which support voice calls from the start, not all LTE networks may support voice calls (the responsibility may be delegated to the UMTS/GSM or the CDMA part of the network).
- There's also cdmaOne and CDMA2000 (1xRTT, EV-DO), these are actually distinct generations, but are backwards compatible with one another; they're mostly popular only in US/Canada and Japan/Korea.
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How do I know if my phone is international?
By checking the model number of your phone in internet. Most probably,Gsmarena's site will show up in 1st or 2nd place which will specify whether it's CDMA or GSM or international. For Example,if you have Samsung Galaxy S3,then the model number -GT-I9300 - is international without LTE.How do you check if iPhone can be used internationally?
There is no such thing as an "International version". All iPhones can be used on any GSM network worldwide (exception being the iPhone 4 CDMA). Whether it must be used with a roaming plan by the home carrier or can be used with a local SIM is dependant upon whether the device is unlocked.Which phones can be used internationally?
Best Unlocked Android Phones for International TravelHow to Keep Your US Phone Number While Traveling or Living Abroad
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