Going Abroad? Pack The Cell Phone

This story was written by CNET's Marguerite Reardon

While the sour economy may be keeping some travelers closer to home this summer, good deals on flights and hotels, and the growing strength of the U.S. dollar are enticing some travelers to grab their passports and book a flight to Europe and other parts of the world. (I happen to be one of them. I just bought a plane ticket to go to France in August.)

And since cell phones are now so much a part of our everyday lives, it's hard to part with them when we hop on a plane to another country. But stories of $3,000 iPhone bills when we return have scared many consumers into turning off their phones or leaving them at home.

But what if you'd like to check in on the kids back home during your trip, or you need to find your travel companions while wandering around the Gothic quarter in Barcelona? Or maybe you've met some nice locals who want to catch up with you later, but they need your number to text you? Well, I'm here to tell you that firing up the cell phone in another country need not be as scary or expensive as you think.

But first you need the facts. To help you get started, I've put together this FAQ that can answer some basic questions about which phones and carriers offer service abroad and how much you can expect to pay. For more information, check out your carrier's Web site.

Also check out a couple of stories written by my CNET Reviews colleague Kent German, who has written a very informative Quick Guide to international phone usage as well as a comparison of some of the hottest world phones on the market.

Does it matter which wireless operator I have if I want to use my phone abroad?

Yes it does. While all of the four major wireless operators in the U.S. can provide international roaming in some parts of the world, some carriers are more limited in where they can offer service based upon the technology they use.

In the U.S. wireless operators use two main cellular technologies: GSM and CDMA.

GSM, or global system for mobile communications, is used throughout much of the world, including in Europe (where it's the standard), Canada, Latin America, the Caribbean, Africa, Australia, and New Zealand, as well as much of Asia and the Middle East. In the U.S., AT&T and T-Mobile USA operate GSM networks. As a result AT&T and T-Mobile have the most extensive networks abroad.

AT&T has roaming agreements in more than 190 countries throughout the world. Its triband and quadband phones will work in most parts of the world, except in Japan and South Korea, where you'll need a special GSM phone that uses the 2100 MHz frequency band. Coverage also extends to some cruise ships.

T-Mobile USA is owned by German telecom provider Deutsche Telekom, which operates its T-Mobile wireless service in seven countries in Europe, including Germany, the U.K., and the Netherlands. T-Mobile has roaming agreements with over 190 countries and also provides service throughout Central America, Australia, much of South America, and some countries in Africa. It also offers coverage on some cruise ships. Like AT&T, service in Japan and South Korea requires a special phone.

CDMA, which stands for code division multiple access, has less worldwide coverage than GSM. The U.S. is one of the biggest markets for CDMA. This is the technology that is used by the largest operator in the U.S.: Verizon Wireless. Sprint's PCS network also uses CDMA. The old Nextel portion of Sprint's network uses a different technology called iDEN, which is used in a limited number of places outside the U.S.

Verizon Wireless, which is jointly owned by Verizon Communications and the world's largest wireless operator Vodafone, has roaming agreements with more than 40 countries for its CDMA service and more than 140 countries that use GSM. Verizon subscribers can use their CDMA handsets to roam in China and Taiwan, Guam, Guatemala, Indonesia, Vietnam, Israel, India, New Zealand, Thailand, Mexico, South Korea, much of South America, and a few Caribbean islands. A software upgrade may be required for some countries. Coverage is available on some cruise ships as well.

Sprint CDMA subscribers can roam in 26 countries and four U.S. territories. And the company has agreements with carriers in more than 100 countries to offer service for a CDMA/GSM phone. The iDEN network only offers services in 11 countries and one U.S. territory. A Sprint CDMA phone should work in most of Central and South America and the Caribbean along with New Zealand, Indonesia, China and Taiwan, South Korea, India, Israel, Thailand, and a few U.S. territories.

As for Nextel users, iDEN roaming is limited to Canada, Chile, Mexico, Argentina, Jordan, Peru, Brazil, the Philippines, Singapore, South Korea, and Israel. Nextel also offers a dual mode iDEN/GSM phone called the Motorola i930, which can be used for voice calling in about 100 countries.

The bottom line is that the devices used on AT&T's and T-Mobile's networks are more likely to work in more countries around the world than devices used on Verizon Wireless or Sprint's networks.

Does this mean that any GSM phone from AT&T or T-Mobile will work in Europe or a GSM network in Asia?

Not necessarily. GSM carriers may be the best choice for globe-trotters, especially those traveling in Europe, but not every GSM phone works in every country. The reason is that different regions of the world use different frequency bands to transmit GSM signals. In the U.S., GSM operators only use the 850 MHz and 1900 MHz frequency bands. In Europe they use the 900 MHz and 1800 MHz frequency bands. Japan and South Korea use the 2100 MHz band. So to make sure you're covered in most regions, you should either get a triband (GSM 900/1800/1900) or quadband (GSM 850/900/1800/1900) phone. Travelers in Japan and South Korea will likely need a new phone. But phones that work in these regions can be rented from your carrier.

Do Verizon Wireless and Sprint have any "world phones" that can be used in countries where GSM is the predominant cell phone technology used?

Yes they do. Verizon offers a few "world phones" that have both CDMA and GSM radios built in. These include, the BlackBerry 8830 World Edition, BlackBerry Storm, and the Motorola Z6c. Sprint also has a few world phones, such as the BlackBerry 8830 World Edition, the Samsung IP-830w, and the HTC Touch Diamond.

Do I need to call my carrier before I leave to activate international calling?

Yes, you should call your wireless provider to make sure your phone is ready to make and receive calls in a foreign country. You can also check with your carrier for the exact rates in the countries where you'll be traveling.

How much will it cost me to use my phone in another country?

This will depend on which carrier you have service with here in the States. Calls will be charged on a per-minute basis. Domestic voice, text message or data plans do not apply when traveling in another country. SMS text messaging is typically the cheapest way to communicate with people in the country where you're traveling and also with your family and friends back home in the U.S.

Here's a summary of what you can expect from the four major nationwide carriers in the U.S.:

AT&T offers customers a World Traveler plan, which offers discounts on most roaming rates in more than 195 countries. The cost is $5.99 a month. And users can sign up for the service for just one month if they are going on a vacation, and they can cancel the service when they return home. But AT&T officials suggest that subscribers pay special attention to their billing cycle to make sure the plan is activated the entire time they are away.

Without a service plan, AT&T charges per-minute roaming rates that vary between 59 cents per minute and $3.99 per minute, depending on the country and roaming carrier used. It costs 50 cents to send a text message and receive text messages in a foreign country, but receiving text messages from someone in the U.S. is free. Sending multimedia messages is $1.30 per message, and receiving MMS messages from the U.S. is free.

T-Mobile USA doesn't offer a special traveler plan. So the company charges per-minute roaming rates. These charges range from 49 cents to $3.99 per minute, based on where you're traveling. Text messages cost 35 cents per message sent and 20 cents to receive each message.

Verizon Wireless charges 69 cents to $2.99 per minute for roaming calls. And it costs 50 cents to send a message and 5 cents to receive a message.

Sprint Nextel offers a $2.99 a month plan to let people traveling to Canada pay only 20 cents per minute for calls. Roaming charges vary between 59 cents to $4.99 per minute for Sprint phones. Text messaging and multimedia messaging are billed as data services. Nextel customers can sign up for a Direct Connect plan that allows them to talk to other Nextel Direct Connect customers in Canada, Mexico, Argentina, Brazil, Chile, and Peru.

What about data charges?

Travelers need to be especially careful of data charges. The rates for data are far more expensive than for roaming voice calls and text messages.

AT&T offers its smartphone customers that have an iPhone, BlackBerry or Windows Mobile device a special data plan to help keep costs down. The cheapest plan offers 20MB of data in 65 countries for $24.99 per month. The 50MB package is $59.99 per month, 100MB package is $119.99 per month, and the 200MB package is $199.99 per month.

Without a plan, users are charged 2 cents per kilobyte. If you're traveling in a country that is not one of the 65 supported in the international data plan, then standard data roaming rates apply.

AT&T officials say that subscribers need to pay special attention to their billing cycle when signing up for an international data plan. If a customer signs up a couple of weeks into the billing cycle right before a trip, the cost of the service will be prorated and so will the total amount of megabytes available. Customers should ask the customer service agent who is signing them up for the plan to back-date their plan to make sure they are getting the full bucket of data while they are traveling on their trip. The monthly plan can be canceled without a hassle the following month.

T-Mobile USA charges $10 per megabyte in Canada and $15.36 per megabyte everywhere else in the world.

Verizon Wireless and Sprint Nextel have varying rates that apply depending on the country you're traveling in.

For more see page 2.

I've heard horror stories about iPhone users who have had outrageously high phone bills after their trips abroad. Why does this happen?

The iPhone was made for data, and as a result it can cause some problems for international travelers, because data rates are typically much higher than voice rates. For example, the iPhone's visual voice mail works over the data network. So when iPhone subscribers receive a voice mail while traveling and their phone is on, that voice mail message will be charged a data rate, regardless of whether that iPhone subscriber checked his voice mail. If iPhone users are having their e-mail pushed to them all the time, this can also jack up the price of their service. And streaming video of any kind over the cellular network will rack up data charges very quickly regardless of whether you're on a smartphone or using a 3G data card.

What can I do to make sure this isn't a problem for me?

Here are some suggestions from AT&T sprinkled with a couple of suggestions of my own.