Because AT&T and T-Mobile have GSM networks, standard in most countries outside the U.S., more of their customers are likely to roam internationally.  Sprint and Verizon Wireless have CDMA networks and their customers’ mobiles won’t work overseas with the exception of specific dual-mode phones that support CDMA domestically and GSM out of the country.

Verizon Wireless is the only mobile operator that does not charge for any calls that ring and then go to voicemail.  Sprint does not charge its CDMA customers in such cases but does charge Nextel customers with iDEN-based phones.

Here’s how AT&T and T-Mobile explain it on their Web sites:

AT&T

“Calls that you do not answer that are routed to the AT&T voicemail system will be charged as an international roaming incoming call to your device.”

T-Mobile

“Unless you switch your device off or activate Unconditional Call Forwarding on your device, you will be billed for calls delivered to your voice mail box while you are roaming internationally.”

It’s even possible for tromboning to occur if you leave your mobile phone off most of the time because it will register with the foreign network and that could still cause calls to be forwarded to your overseas location and back – resulting in a hefty bill when you arrive home.  In addition, depending on the policy of the foreign operator, the bill might be for the call to your location and back to your home network.

DO YOU CHARGE FOR UNANSWERED CALLS THAT FORWARD TO VOICEMAIL?

It runs on Palm’s easy-to-use (if a little dated) Palm OS 5.4.9 and features a nicely-sized full-color 2.2” touch screen with 320 x 320 pixel resolution.

I found the five-way navigation button easy to use and the keypad made e-mail and texting a simple matter.  You can dial phone numbers from either the touch screen or the keypad – it’s good to have a choice since dialing with a combination QWERTY/phone keypad is always a bit tricky.  The Centro also supports push-to-talk service, useful for staying in immediate touch with colleagues and friends.

Nice touches abound, including built-in XM Radio, allowing you to take 25 of the best channels with you.  My online complaint: unlike the Sprint version, which supports 3G data, the GSM version only supports EDGE (Enhanced Data rates for Global Evolution) data services, which, while faster than GPRS at 100-130 Kbps, is still much slower than typical 3G speeds.

–David M. Goldes is a Contributing Editor of Executive Road Warrior and President and Senior Analyst at Basex, a knowledge economy research firm.

The Bosch World 718, introduced in 1998, was the first true world phone.

Why is it then that many business travelers fall off the communications grid when they travel internationally?

Perhaps the greatest reason is the fact that the United States has multiple mobile telephone standards (the two most popular are CDMA and GSM, but there are others as well).  The rest of the world, with the exception of Japan and some parts of South America, uses only GSM.

GSM was developed with the business traveler in mind.  In 1982, the Groupe Spécial Mobile (GSM), a study group, was created by the Conference of European Posts and Telegraphs (CEPT) to combat the problem of incompatible mobile phone systems in European nations.  One of the goals of the GSM was to create a pan-European system that would allow a business traveler to drive across multiple national borders while continuing the same phone call.

The rest, as they say, is history: GSM specifications were published in 1990 and the first network went online in 1991.  Today, out of 2.53 billion mobile subscribers worldwide, 83% are GSM and UMTS (the 3G successor to GSM).

To keep business travelers connected, here is a primer on everything you need to know on the subject.

For starters, not all GSM phones will work everywhere.  Phones from different countries operate on different frequencies, although these are standardized by region.  So a GSM phone designed solely for North America won’t work in Europe.

To combat this, the multi-band mobile phone was designed.  The first was the World 718 introduced by Bosch in 1998.  I remember the first time I used mine (also in 1998); en route to a meeting in Berlin, I made a stop in Zürich.  After disembarking, I turned the phone on and was amazed to see Swisscom pop up on the screen (I was rather skeptical back then).  Calling was as easy as dialing from the U.S.  And anyone who dialed my phone’s number from the U.S. found me across borders and time zones.

With the right phone and service (see Selecting Your Service Provider), executive road warriors can place and receive calls in ca. 190 countries, with wireless data roaming in more than 100 countries.

TIP: Be aware of time zone differences and turn your phone off when going to sleep.  With time differences of many hours, someone may wind up calling you while you are sound asleep.

Technology has improved greatly since 1998.  Now instead of tri-band phones, we have quad-band and five-band phones.  I’ve looked at almost every phone out there and selected the best performing and easiest to use phones for your consideration.

See reviews of four world phones, the Research in Motion BlackBerry Pearl, the Palm Treo 750, the Palm Treo 680, and the Sony Ericsson W810i.

GLOSSARY

GSM – Groupe Spécial Mobile (Global System for Mobile Communications), 2G (Second Generation Mobile Phone Technology) voice service, offered by T-Mobile and AT&T (formerly Cingular) in the U.S.

GPRS – General Packet Radio Service, 2G data service, offered by AT&T and T-Mobile

EDGE – Enhanced Data rates for Global Evolution, an enhancement of GPRS, sometimes referred to as 2.5G, average throughput of 80 – 130 Kbps, offered by AT&T and T-Mobile

UMTS – Universal Mobile Telecommunications System, 3G voice service, offered by AT&T and T-Mobile (planned for 2007)

HSDPA – High Speed Downlink Packet Access, 3G data service, average throughput 550-800 Kbps, offered by AT&T and T-Mobile (planned for 2007)

CDMA – Code Division Multiple Access, 2G voice service, offered by Verizon and Sprint in the U.S.

CDMA2000 – a family of 3G mobile telecommunications standards and the second generation of CDMA technology.  Offered by Verizon and Sprint in the U.S.

SIM – Subscriber Identity Module, a smart card that holds the telephone number of the subscriber, encoded network identification details, the PIN,  and other user data including the phone book

SELECTING YOUR SERVICE PROVIDER

Both T-Mobile and AT&T offer GSM service in the United States and allow customers to roam internationally.  In most cases, you need to tell your mobile operator that you will be roaming internationally but there is no charge for having this added to your account.

In general, I have found that T-Mobile offers better pricing but this isn’t always the case (see chart, International Roaming Fees).  AT&T offers discounted rates for calls from ca. 80 countries if you sign up for the company’s World Traveler program (a $5.95 per month fee).

If your mobile is unlocked, you can insert a local SIM (see glossary) and place and receive phone calls at the same rates as locals.  In most countries, incoming calls are free under the Calling Party Pays (CPP) system. This means that calling a mobile phone number from a landline is more expensive than calling another landline phone.  Incoming text messages are also usually free.  A prepaid SIM can be purchased from almost every local mobile operator (examples would include A1 in Austria, T-Mobile in Germany, SingTel in Singapore, and Vodafone in the U.K.)  Be aware that most prepaid plans are good only in their home region and roaming across a border will result in roaming fees that are generally higher than those charged by U.S. mobile operators.

An additional option is to use Skype or a similar Voice-over-IP service, where rates are generally pennies per minute.  A laptop or phone with Wi-Fi capabilities is required to access the service, as is access to the Internet.

IS YOUR PHONE LOCKED?

Most mobiles purchased with a contract from a mobile operator are “locked,” which means one cannot use a different mobile operator unless the device gets unlocked.  T-Mobile will provide an unlocking code for customers who are traveling overseas as long as they are not a brand new customer.  In addition, there are scores of legal unlocking services which, for a fee, will provide a code to unlock one’s mobile.

INTERNATIONAL ROAMING FEES

Calling from                T-Mobile WorldClass AT&T   AT&T World Traveler*

Australia                     $1.49                          $1.69              $1.29

Belgium                       $ .99                           $1.29               $1.29

Austria                         $ .99                           $1.29                $ .99

Finland                        $ .99                           $1.29                $ .99

Germany                     $ .99                           $1.29                $ .99

Greece                        $1.49                           $1.29               $1.29

Hong Kong                $1.49                           $2.29               $1.99

Israel                          $2.99                           $2.49               $1.99

Malaysia                    $1.99                           $2.29               $1.99

Qatar                           $1.99                           $2.49               $2.49

Taiwan                        $1.49                           $1.99               $1.29

Text msg (sent)        $ .35                            $ .50                $ .50

Text msg (rec’d)      $ .10*                           **

*or pulled from monthly bucket

**charges vary based on individual plan

(Source: T-Mobile and AT&T Web sites)

–Jonathan B. Spira is the Editor of Executive Road Warrior and Chief Analyst at Basex, a knowledge economy research firm.

Both T-Mobile and Cingular offer the BlackBerry Pearl by Research in Motion, although only T-Mobile has the new white Pearl.  The Pearl is an 88 gram quad-band device with a 240×260 color display.  It supports GSM/GPRS and EDGE (Enhanced Data for GSM Evolution) and includes a memory expansion slot for a MicroSD card.  It supports BlackBerry e-mail, public instant messaging via AOL, ICQ, MSN, and Yahoo, corporate instant messaging (Lotus Sametime), an HTML browser, and uses RIM’s SureType keyboard technology.  Phone features include voice activated dialing, a speakerphone, simplified call management for conference calling and smart dialing, and Bluetooth wireless technology.

Unlike other BlackBerry devices, the Pearl has a modified QWERTY keyboard with shared keys in many positions (i.e. E and R and U and I).  This gives it a more phone-like form factor although typing suffers slightly (keep in mind that most people do not type out War and Peace with a handheld device anyway).

The Pearl is my personal favorite due to the combination of the candy bar mobile telephone form factor with PDA functionality. The pearl-like trackball allows for very easy navigation and the display provides sharp clear text.

In short, it’s a better mobile phone with no compromises.

PALM TREO 750

The brand new Palm Treo 750 is available from Cingular at $399 and unlocked from Palm at $649.

The Treo 750 is the first Palm five-band device I’ve tested. The UMTS service from Cingular supports simultaneous use of phone and Web or e-mail.  If UMTS is not available, the 750 will fall back to EDGE. The Treo 750 will, for the time being, arrive enabled for UMTS with a free upgrade, scheduled for later in 2007, to Cingular’s high-speed HSDPA technology.

It runs Windows Mobile 5.0 with Direct Push Technology, and supports e-mail, messaging, Web browsing, productivity tools, as well as many other applications.  The 750 features a full QWERTY keyboard (an improved design), 1.3-megapixel camera, a 240×240 touch screen, and support for Bluetooth stereo headsets.  The built-in 60 Mbytes of user-available storage can be expanded to 2 Gbytes via a miniSD slot.

This is not your ordinary Windows Mobile: Palm has greatly enhanced the interface, adding a new messaging application with threaded chat for text and MMS message; Today Screen enhancements, including a fast dial-by-name feature; support for call and voicemail management from the Today Screen, including VCR-like controls such as rewind, fast forward, and delete for voicemail; and my personal favorite, the ability to “ignore” a call while simultaneously sending a quick text message to the caller such as “in a meeting – will call back soon” directly from the incoming call screen.

I was skeptical on the robustness of Windows Mobile as the Treo 700w I’ve used crashed frequently (compared to the Treo 700p, which uses the Palm operating system and didn’t crash at all) but the Treo 750 did not share this trait.

I was happy to see that the 750 has a hidden aerial, a design trait started with the Treo 680, with which it shares its basic form factor.  The 750 has an elegant soft-touch exterior (no need to purchase a case) and despite its size, feels comfortable in your hand.  If you want 3G service and a standard QWERTY keyboard, this is an excellent choice.

PALM TREO 680

If your mobile telephony needs don’t require broadband, the Treo 680 is worthy of consideration.

The Treo 680 is a GSM/GPRS/EDGE quad-band mobile device.  It supports e-mail, Web browsing, messaging, multimedia, calendar, and contact management.  It has an internal antenna and slim form factor, with a 320×320 color screen and full keyboard.  It also supports Bluetooth 1.2, which includes support for multiple Bluetooth connections.

It’s available from Cingular for $199; an unlocked model from Palm is available at $399.  The twist: the unlocked version is available in four colors: crimson, copper, arctic, and graphite.

The Treo 680 uses the time-tested Palm operating system.  Compared to older Treos, including the 700 family, it’s faster to use (thanks to an improved phone application) and feels more comfortable in the hand.  It also has a much improved keyboard (the buttons are redesigned, making thumb-challenged typists less clumsy). Similar to the Treo 750, calls arriving at an inconvenient time can be ignored while sending out a quick text message to the caller.  It also supports the display of threaded chats.

Mobile business travelers can access various Cingular-enabled wireless e-mail solutions as Cingular Xpress Mail, Microsoft Exchange Active Sync, and Good Mobile Messaging from Good Technology, as well as e-mail from POP3 and IMAP accounts.

If you’ve lusted after a Treo and price is a consideration, you need go no further than the Treo 680.

SONY ERICSSON W810i

A slightly different path is taken by Sony Ericsson, with its line of Walkman phones.  The W810i is a small, candy bar form factor mobile that has a large, high resolution color display and a very clear, easy-to-use user interface.

Its design is reminiscent of one of my all-time favorite mobiles, the Sony Ericsson T610. The W810i allows the business traveler to take his own music with him, whether it’s from CDs or music stored on the computer. It supports MP3 and AAC formats.  You can also purchase new music from mobile operator specific over-the-air download services.   Music is controlled by the dedicated Walkman button (which sometimes can be inadvertently pushed, the only downside I found in testing the device).

The W810i also has a 2 megapixel camera built in, which is really good for a mobile phone (most still have 1.3 megapixel sensors at best).  You can share photos with your computer or other devices including Bluetooth-enabled printers using Bluetooth.

What impressed me most about the W810i is the form factor – it feels great in your hand and doesn’t take up much pocket space.  If you are listening to music and a call comes in, the music pauses.  You can also operate it in a music-only mode for air travel.  This is the only mobile in our review that isn’t a smart phone.  If you want a great phone and music for your business trips that will work in 190 countries, look no further.

–Jonathan B. Spira is the Editor of Executive Road Warrior and Chief Analyst at Basex, a knowledge economy research firm.