By Robert Strohmeyer, PC World

Here's an overview of the technology now available, the product options, and how well and far the devices can travel.

Work doesn't stop just because you've left the office. If anything, you just multitask more. So it's critical to get a mobile phone that can work as hard as you do. Today's business handsets have made a massive evolutionary leap from the simple pocket talkers of yore, offering surprisingly effective solutions for managing your calendar, your contacts, and even your business data, no matter where you are. There is no single greatest handset for all users, but with a little bit of forethought, you can easily choose the best phone and service plan for your own business needs.

Smart phones

Built explicitly for business users, these intelligent mobiles make quick work of e-mail, Web surfing, and business data.

BlackBerry
The standard bearers of business phones, RIM BlackBerry handsets are defined by their intuitive keypads and smart, stable software. Because of their wide adoption among large corporations, BlackBerrys integrate easily into business networks of all sizes. Every major cellular provider offers at least a few BlackBerry options, complete with e-mail and data services that let you easily synchronize the handset with PCs and servers back at the office. Traditional BlackBerrys, such as the 8700 series, sport spacious QWERTY keypads for quick thumb typing, while the smaller Pearl models use a technology called SureType to allow fast typing with multiple letters assigned to each key.

Windows Mobile
Rapidly gaining ground among business users, Windows Mobile devices such as the Motorola Q are designed to offer a familiar Windows-style appearance for business users, along with simple data syncing with Microsoft Outlook. Like BlackBerry, Windows Mobile offers a variety of network-side connectivity options so a small company with just a few handsets can grow into a large company with a fleet of handsets without having to throw away all the phones in the process.

Palm
Palm Treo smart phones maintain a prominent place among business handsets, thanks in large part to their simple interface. In recent years, Palm has extended its offerings to include Windows Mobile as an option, and also offers BlackBerry Connect service, which makes it a viable choice for larger business networks.

Symbian
Less known in North America than in Europe, Symbian is the primary operating system used on Nokia smart phones. It is powerful and versatile, with a variety of options for integration with business networks, although North American small business users will find it more challenging to implement than either BlackBerry or Windows Mobile, because it simply enjoys a smaller market share here--and therefore, fewer support options--than its competitors.

iPhone
In June, Apple made its first foray into the world of mobile phones with the iPhone, a svelte smart phone that integrates e-mail, a Web browser, and an iPod into one device. It remains to be seen whether the entertainment-centric iPhone will make the jump into the business world, but it's certainly a promising platform.

Linux
The open source Linux operating system is enjoying rapid growth on cell phones, although it has yet to break into the world of business smart phones. Currently a number of initiatives are in the works to create phones as powerful and versatile as the BlackBerry, but they have yet to materialize in the marketplace. It will, however, be interesting to watch as companies like Motorola apply more effort to Linux development on phones.

A Note About Camera Phones
Nearly every cell phone on the market today includes a small camera, usually of fairly low quality, built into its chassis. This can spell trouble for businesses that place a premium on protecting their trade secrets, and it's worth considering this problem if you're planning to hand smart phones to your workforce. Fortunately, many of the premium handsets mentioned above are available in both camera-equipped and cameraless models.

Technologies

Your phone's performance in the field will depend largely on the technology it uses to connect. Here's a look at the leading technologies.

GSM/EDGE/UMTS
The Global System for Mobile communications (GSM) is the leading cellular technology worldwide. In North America, it is used by AT&T and T-Mobile. GSM phones use small data cards, called SIM cards, to store information about the user's account, which makes it easy to upgrade to a new phone. Just pop your SIM card out of your old phone and into your new phone, and you can start talking right away. For high-speed data services, GSM phones commonly use a technology called EDGE (Enhanced Data Rates for GSM Evolution). EDGE phones typically offer a maximum data rate of around 236Kbps, which is slow by 3G (third-generation) cellular standards. For this reason, EDGE is not generally considered a 3G technology.

In addition to EDGE, GSM networks also sometimes use a faster technology called UMTS (Universal Mobile Telecommunications System) for genuine 3G data rates of up to 3.6Mbps, which is quite fast. To reach the higher UMTS data rates, you must have a newer device that uses the HDSPA (High-Speed Downlink Packet Access) protocol. Unfortunately, UMTS deployment has been slow in many parts of North America, so it's still not available in all areas.

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.

Carriers

Choosing the right cellular carrier 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&T is 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, the Verizon Wireless network is based on CDMA and EV-DO technology. Verizon's EV-DO handset selection is impressive, and includes about 10 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, Sprint has 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's GSM 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.

Mobile e-mail

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.

Data Services

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.