How to: Buy a Mobile Phone

CDMA/EV-DO The other major cellular technology is Code Division Multiple Access (CDMA), which is used by Sprint and Verizon Wireless. Unlike GSM phones, CDMA handsets are hard-coded with a unique ID number that is recognized by the network to allow connections, so there is no SIM card. The 3G data technology for CDMA phones in North America is called Evolution-Data Optimized (EV-DO). EV-DO offers data rates of up to 3.1Mbps. Unlike UMTS, EV-DO data service is nearly ubiquitous throughout all major American metro areas.

Choosing the right cellular carrier will is critical to ensure quality connectivity for your business travels. Here's what you can expect from the major U.S. carriers.

AT&T Formerly known as Cingular,AT&Tis one of the two largest carriers in the U.S. Its GSM-based network uses predominantly EDGE data service, which is generally slower than the EV-DO service offered by Sprint and Verizon Wireless. However, the company has been rolling out a faster UMTS for a couple of years now. Only two AT&T phones feature the faster UMTS data service. In general, AT&T's EDGE data plans tend to cost significantly more than the EV-DO plans offered by Verizon Wireless and Sprint. International roaming agreements make it easy to take your AT&T GSM phone abroad without missing important calls.

Verizon Wireless Matching AT&T in size and coverage, theVerizon Wirelessnetwork is based on CDMA and EV-DO technology. Verizon's EV-DO handset selection is impressive, and includes about ten offerings for BlackBerry, Windows Mobile, and Palm OS. Because CDMA is less broadly adopted in Europe and Asia than in the U.S., traveling abroad can be more problematic with Verizon handsets, although the company does offer some handsets that work on both CDMA and GSM networks.

Sprint Following its merger with Nextel,Sprinthas arisen as a major force in the cellular world, and now offers a large 3G EV-DO data network with about nine smart phone offerings for BlackBerry, Windows Mobile, and Palm users. Like Verizon, Sprint's phones can pose problems for international travelers, but the company does offer special phone loans for overseas trips. Of the three leading companies, Sprint has the most confusing billing plans, although service costs for voice and data are roughly comparable to Verizon.

T-Mobile More focused on home users than businesses,T-Mobile'sGSM offers EDGE data services over roughly 75 percent of the company's service area. While T-Mobile does boast a few good business smart phones, including BlackBerry and Windows Mobile handsets, it remains less focused on the needs of business users than its three major competitors. The company does not offer any true 3G data service.

Whether you have five employees or 50,000, you have several options for getting your e-mail on your mobile phone.

POP3 The most common type of mail server is the POP3 server. If your small business hosts its Internet services through a third-party provider, chances are this is the type of server you use. All true smart phones feature a POP3 mail client, which you can easily configure by entering the address of your server, your username, and your password. POP3 clients connect to the server at regular intervals (or manually, when you tap the Send/Receive button) to check for new mail and send out your messages.

Exchange Medium-size to large businesses often use Microsoft Exchange to manage e-mail and calendars together. This powerful server application makes it easy for workers to share calendars, automatically schedule appointments, and manage shared company resources such as conference rooms. Many smart phones support Exchange servers, which lets them automatically sync all of your calendar, contact, and mail data through one connection. As you might expect, Exchange support tends to be particularly good on Windows Mobile devices.

BlackBerry Known for innovating "push" technology, BlackBerry e-mail uses a specialized server (either on the Internet or on your business network) to push incoming e-mail straight to your handset when it comes in, rather than make you wait until your phone syncs up with the server. BlackBerry Internet Service is most commonly managed through your wireless carrier, although some larger companies manage their own BlackBerry enterprise servers.

Proprietary Sync Systems In addition to the technologies described above, some wireless carriers also offer their own services to sync e-mail and other data to your mobile device. Verizon Wireless offers Wireless Sync, AT&T offers XPress Mail, and various other options are also available. These services often involve installing an application on your desktop PC, which then relays information over the Internet to your handset, keeping your Outlook schedule, contacts, and e-mail in sync between the PC and the phone.

Business handsets offer a variety of data connections to keep you in touch with the Internet and your office.

Internet All phones today, from the most feature-laden smart phones on down to the simplest slim handsets, offer Internet access for the Web and messaging. The quality of that Internet experience will depend entirely on the size and resolution of the screen, the quality of the keypad and controls, and the speed of the data connection. If you select a handset with a fast UMTS/HDSPA or EV-DO connection, your mobile Web surfing will likely be just as fast as what you're accustomed to at the office.

VPN If you have a Virtual Private Network (VPN) set up at your office, you can access it through a smart phone. Many devices come with a VPN client application pre-installed, making it easy to configure your device for secure access to your network's servers. This is particularly useful when you need to grab an important file while you're away from the office, and you don't have time to boot a laptop.

Wi-Fi Increasingly, mobile handsets are beginning to offer Wi-Fi connections for data services. This lets you surf at high speed without having to go through your cellular carrier's network. It also means you can access any servers on your network as if you were at your desk.