Many American cellular phone users planning to travel abroad wonder whether their cell phones will work while they are overseas. Unfortunately, the world of international roaming often seems intentionally designed to confuse consumers. For example, customers of Verizon Wireless and Sprint-Nextel will likely find that their phones will not work at all in most countries since they work on the CDMA and PCS/iDEN standards, respectively, and most of the rest of the world operates on the GSM standard. T-Mobile and AT&T Mobility customers are in more luck since both companies’ networks operate on the GSM standard.

Beyond operational worries, pricing is also likely to be an expensive headache. International roaming (i.e. using an unmodified U.S. cell phone to make calls overseas) is likely to cost $1.50-$2.00 per minute or more, depending on location. In many instances, customers can buy a replacement SIM card (the card in all GSM phones that holds network and customer information) in their destination country and use a prepaid service.

The Yackie Mobile SIM card allows you to roam in 200 countries, with unlimited free incoming calls in 150 of these countries. Users have the option of choosing a free personal phone from a list of 24 countries to attach to their SIM card upon registration. With Yackie Mobile incoming calls are only ¢29/minute and outgoing calls in most countries are ¢39/minute. Yackie Mobile does not require a contract and is simply pay as you go.

Yackie 101: GSM V.S. CDMA

In cellular service there are two main competing network technologies: Global System for Mobile Communications (GSM) and Code Division Multiple Access (CDMA). Understanding the difference between GSM and CDMA will allow you to choose a carrier that uses the preferable network technology for your needs.

The GSM Association is an international organization founded in 1987, dedicated to providing, developing, and overseeing the worldwide wireless standard of GSM. CDMA, a proprietary standard designed by Qualcomm in the United States, has been the dominant network standard for North America and parts of Asia. However, GSM networks continue to make inroads in the United States, as CDMA networks make progress in other parts of the world.

Data Transfer Speed:

With the advent of cellular phones doing double and triple duty as streaming video devices, podcast receivers and email devices, speed is important to those who use the phone for more than making calls. CDMA has been traditionally faster than GSM, though both technologies continue to rapidly leapfrog along this path. Both boast “3G” standards, or 3rd generation technologies.

EVDO, also known as CDMA2000, is CDMA’s answer to the need for speed with a downstream rate of about 2 megabits per second, though some reports suggest real world speeds are closer to 300-700 kilobits per second (kbps). This is comparable to basic DSL.

GSM’s answer is EDGE (Enhanced Data Rates for GSM Evolution), which boasts data rates of up to 384 kbps with real world speeds reported closer to 70-140 kbps. With added technologies still in the works that include UMTS (Universal Mobile Telephone Standard) and HSDPA (High Speed Downlink Packet Access), speeds reportedly increase to about 275—380 kbps. This technology is also known as W-CDMA, but is incompatible with CDMA networks. An EDGE-ready phone is required.

In the case of EVDO, theoretical high traffic can degrade speed and performance, while the EDGE network is more susceptible to interference. Both require being within close range of a cell to get the best speeds, while performance decreases with distance.

Subscriber Identity Module (SIM) cards:

In the United States only GSM phones use SIM cards. The removable SIM card allows phones to be instantly activated, interchanged, swapped out and upgraded, all without carrier intervention. The SIM itself is tied to the network, rather than the actual phone. Phones that are card-enabled can be used with any GSM carrier.

The CDMA equivalent, a R-UIM card, is only available in parts of Asia but remains on the horizon for the U.S. market. CDMA carriers in the U.S. require proprietary handsets that are linked to one carrier only and are not card-enabled. To upgrade a CDMA phone, the carrier must deactivate the old phone then activate the new one. The old phone becomes useless.

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