Call it the end of downtime -- All those offline hours wasted in useless conference sessions or at the airport -- and the start of rich applications accessible virtually anywhere. Whether your preferred device is a handheld or a notebook, in a year or so 3G networks will effectively reinvent how your mobile enterprise conducts business.

Say, for example, you're at a client site and suddenly discover that you need more details on a consulting project. No problem. You'll turn on your device and connect to the corporate servers that run your enterprise apps. You'll be able to check e-mail and to participate in workgroup projects as if you were at your office. Colleagues may not even know you're off-site because you'll be doing your normal work in the normal way.

That has been the big promise of 3G cellular networks -- one that has gone unrealized for half a decade, as cellular carriers postponed deployments and instead rolled out low-speed (30Kbps to 70Kbps) 2.5G networks, which even dial-up modem connections can outrun. 'You can't run rich applications" on 2.5G networks, concedes Kenny Wyatt, assistant vice president of integrated solutions at Sprint PCS .

But this year, carriers are finally starting to make good on their word. The first parts of real 3G networks are already here, offering throughputs between 200Kbps and 400Kbps equivalent to the early DSL networks that revolutionized the home office. Verizon Wireless has deployed the CDMA2000 1xEvDO (evolution, data optimized) technology in no fewer than 15 urban areas and plans to make the service available nationwide by 2007. Sprint PCS promises to start offering its own EvDO service this fall in a handful of cities before expanding nationally. Cingular Wireless now offers in six cities the UMTS (Universal Mobile Telecommunications System) service it inherited from AT&T; Wireless and plans to roll out a faster HSDPA (High-Speed Downlink Packet Access) service later this year. T-Mobile plans to start deploying HSDPA in 2006.

After carriers have completed their rollouts, 3G should be available broadly enough -- and with enough user capacity -- for enterpises to rely on it. Between now and then, however, businesses will have to decide whether the available coverage and capacity will be sufficient for their needs. Given the wireless industry's history of overstated claims for earlier-generation data services and its tendency to focus on consumer applications such as downloadable ring tones and camera phones, the question remains whether the carriers will truly follow through on their 3G promises, says Phil Smith, vice president of global solution marketing at IT consultancy Unisys .

EvDO is the 3G technology for CDMA-based networks, such as those used by Verizon and Sprint . UMTS and HSDPA are the 3G technology for GSM-based networks, used by Cingular and T-Mobile. All-you-can-eat service costs approximately $80 per month and typically includes access to 2.5G networks -- CDMA2000 1xRTT (Radio Transmission Technology) for CDMA users and GPRS and EDGE (Enhanced Data GSM Environment) for GSM users -- to ensure connectivity when users move outside 3G coverage areas.

Although 3G has the potential to revolutionize notebook users' productivity on the road, its benefit for handheld users is less clear, at least in the near term.

Notebook Users: Take Your Office With You

Sandy Potter -- vice president of business development at Canvas Systems, a provider of refurbished computer equipment -- has experience using 2.5G networks and has found them significantly lacking. They were so slow, she recalls, that she brought her computer into the IT staff because she thought it was failing. Her timing was good: IT was testing an EvDO service and gave her a card. The difference in performance was dramatic.

"It's as though I'm sitting at my desk. It allows me to be out of the office for five or six days and not be backlogged when I come back," Potter says. "It's all about how you can do more deals in the same time -- and not have a backlog that takes a weekend to go through or interrupts the group's workflow." Another advantage is that, when visiting clients, Potter and her staff don't have to use the client's network to get broadband access.

"3G provides the potential for enterprise services to run over the wide area network," says Mark Morell, director of strategic marketing for carrier networks at Nortel Networks, which provides the carriers equipment for their 3G systems. "We expect to see mobile users have the same services and capabilities as in their offices."

When fully deployed, "3G will reduce the expectation gap and the delivery gap between wireless and wired connections," says Antoine Blondeau, vice president of wireless at Salesforce.com . "The user experience will compare to the Web experience." And Blondeau speaks from personal experience: "I've had an EvDO card for a while, and it works nicely. I'm using my laptop more often, and I'm doing more complex tasks [over the air] with it."

Oracle , for example, expects the arrival of 3G to change how its customers use Oracle software on the road, says Jacob Christfort, vice president of server technology at the database provider. "In the 2.5G world, we did not see much use of our eBusiness Suite [by mobile users]. 3G will make these Oracle applications available to them," he says. It also should ease the workload for the IT group: With 3G connections, "IT just manages a Web-based application and no longer needs to worry about synchronizing databases since there's no longer a need for a parallel system for mobile users," he says.

For IT, providing 3G access to notebook users is simple: Subscribe to the service and hand out 3G modem cards to users. Novatel Wireless currently offers EvDO and UMTS modem cards and plans to support HSDPA this fall. Sierra Wireless also provides EvDO cards and plans to release UMTS/HSDPA cards in the future. Current 3G modems aren't backward-compatible with 2.5G networks such as 1xRTT and GPRS, so users would need both modems if they frequently travel in non-3G areas. When they lose 3G service, they'll need to swap their 3G modem card with a 2.5G modem card and then connect to the 2.5G network. When they re-enter 3G terrain, they'll need to revert to the 3G card. Fortunately, new models planned for the fall will support both 3G and 2.5G networks, thereby eliminating the need to carry two modem cards.

Users access the corporate services through the same remote-access protocols that any other remote employees would use. "You log in to the network just as if you were using a DSL or cable modem," Nortel's Morell says. That could mean the use of VPNs, Webbased access, or terminal emulation such as Citrix Systems servers - the enterprise uses the same remote-access mechanism provided to users from a home broadband connection, an Internet terminal, or a Wi-Fi hot spot .

In an effort to secure their 3G networks, carriers have tapped technology built into the CDMA and GSM protocols to encrypt over-the-air data and hinder access by snoopers. Customers, however, remain responsible for securing connections from carrier networks through the public Internet and into their enterprise systems and must secure user devices themselves. That means 3G users will have the same security methods -- encryption , VPNs, hardware IDs, password challenges, and so forth -- as any other remote user supported by their enterprise.

This standard remote-access security could be less than enterprises are used to with messaging services such as those from Research In Motion (RIM) and Good Technology. That's because the messaging services typically provide a high level of encryption and initiate the connection to the device, so the enterprise retains full control over the communications. As is any other remote device, a 3G-connected device is capable of initiating connections itself. And the encryption level implemented by IT may be less than what RIM or Good Technology offer.

The increased reliance on mobile devices encouraged by 3G networks means that IT should consider developing a mobile security policy that includes protecting the device's contents as well as its access to enterprise servers, says Marvin Chartoff, CTO of global infrastructure services at Unisys. Enterprises will also demand the ability to "kill" a lost or stolen device so that its data can no longer be accessed, he adds.

Although disabling a device remotely is possible over 2.5G networks, a faster, more reliable 3G connection "means the minute that I know the device is lost, I can zap it," says Ojas Rege, senior director of mobile solutions at Sybase mobile subsidiary iAnywhere. The faster speeds of 3G increases the chances of the "kill" command being received by the device before the thief prevents that action.

Wi-Fi networks, by contrast, often use inferior security mechanisms, and in many cases not even the basic security has been turned on. Wi-Fi networks can be deployed by almost anyone, so the level of security know-how often varies widely (infoworld.com/2577).

Incremental Gains for Handheld Users

The arrival of 3G will have a less dramatic effect on handheld users because these devices and their applications were designed mainly for offline uses, with occasional synchronization via a cradle or slow cellular connection necessary when the user moves from one location to another.

Good Technology, which provides a messaging service used largely by executives on handheld devices, expects 3G to help bring richer applications to handheld devices. "EvDO and HSDPA will help make GoodAccess take off," says John Friend, CTO of Good Technology.

GoodAccess allows IT to build and deploy applications that connect to back-office products such as SFA and ERP , but the slow 2.5G networks have kept adoption low, Friend notes. (Executives at RIM, makers of the Black-Berry messaging device and service, declined to comment on how the company might take advantage of 3G connections, although in Europe it has used the technology to provide application access similar to GoodAccess.)

Salesforce.corn's Blondeau expects both IT and third-party software developers to start taking high-speed access into consideration as they create mobile applications. That would mean less reliance on storing local data, for example. "The need for a fully asynchronous architecture is reduced," he says.

Blondeau also expects Web services to increasingly support access from handhelds, by using technologies such as DHTML and XML to present an appropriate interface for the handheld's smaller screen and limited input capability -- reducing the need for separate mobile applications.

Given that 3G networks will also allow over-the-air management of mobile device, enterprises will be able to upload application and anti-virus updates -- files too large to transmit across 2.5G networks. Both Good Technology and RIM already offer management services for their devices. Both devices are part of an overall service that includes a messaging server at the enterprise, so it makes sense for the enterprise to manage that service directly.

For carrier-supplied 3G services, Salesforce.com's Blondeau says it's natural for the carriers to provide such services, rather than having IT deploy it, because carriers will be rolling out multiple applications over multiple devices and thus must figure out the connectivity and management capabilities anyway. Anticipating this demand, Sprint PCS will offer its Managed Mobility Services later this year. In addition to updating software and disabling missing devices, the service will allow IT to provision services to new users, including specifying their capabilities and access rights. Cingular Wireless is contemplating a similar service.

If the carrier provides the management infrastructure, the enterprise still must manage the devices and services using a Web application. But enterprises that prefer not to outsource their management activities don't have to: A few companies -- including iAnywhere's XcelleNet division and Intellisync (formerly named Pumatech) -- provide their own device management platforms that work via Wi-Fi and cellular networks.

The 3G handheld may provide an additional benefit, notes Good Technology's Friend: With a Bluetooth or UWB (Ultra Wideband) wireless connection, a 3G handheld can act as a modem for a laptop, so a user could share one 3G service plan between the two devices. That would mark a real revolution: a cell phone giving the notebook real broadband speed.

Even if you end up with a separate 3G card for your notebooks, that broadband speed will untether business travelers and field forces from hotels, hot spots, and other location-specific connections. Assuming the 3G networks are rolled out broadly and with sufficient capacity, that will keep you connected and as productive as any desktop employee - that is until you run out of battery power.