Cellular digital packet data service is going away. It'll still be there tomorrow — much to the relief of those public-safety and government agencies that use the technology for mission-critical communications — but it's not long for this world.

That's the bad news. The good news, according to carriers, vendors and even those who use the service, is that the new technologies will be better. The transition will be painful but achievable, not a small thing considering some technology transitions. And the onerous — some would say ridiculous — cut-them-off-now deadlines that major carriers Verizon Wireless and AT&T Wireless first suggested last year have been amended to give CDPD users time to find a place to go before the service goes out.

Still, something upon which first responders heavily depend is roiling in turbulent waters as a space not used to change is being asked to give up a dependable service and pick something new off the shelf.

CDPD, in brief, is a specification for supporting wireless access to the Internet and other public packet-switched networks via cellular telephone equipment. Everyone agrees that at 19.2 kb/s it's unfashionably slow, but it's also highly reliable and can cover large areas with dependable service that outperforms anything the commercial cellular providers deliver to normal consumers. Yet to be decided is whether CDPD's more glamorous replacements will follow the same workmanlike model that first responders require or will be more like the unreliable cellular model that public safety finds unacceptable.

The time extension gives first responders the chance to find out what the future holds and look at some of the new technologies that cellular providers are suggesting will do the job. While not ideal, this is much better than what was first suggested.

“It was supposed to be disconnected in June 2004 — it will be June 2005,” said Michael Bedwell, public-safety systems manager of information technology for the City of Aurora, Colo., whose system uses AT&T Wireless. Verizon Wireless has given CDPD users until the end of 2005.

The cellular providers almost certainly didn't make the change of their own free will or good nature.

“I would imagine a number of public-safety agencies complained, and I would imagine a number of other customers complained about the short notice,” said Glen Nash, a senior telecommunications engineer for the State of California and past president of the Association of Public-Safety Communications Officials. “It was about six months, maybe less, and then the service was going to be discontinued.”

Compare that with how long it usually takes a government agency to move to new technology, and it's easy to see why the complaints probably overwhelmed wireless carriers.

“Traditionally public-safety agencies have looked at about a 10-year replacement cycle,” said Nash, noting that such a cycle provides the necessary time to work out the technology kinks and ensure reliability. People's lives and property are dependent upon our use of these systems, and we need to know that it's going to work and how it's going to work. We're comfortable with older technologies.”

They were comfortable with CDPD — and now they can keep that comfort level a little longer.

The extensions, Bedwell said, help cities like his determine how to migrate to other wireless solutions such as Wi-Fi, GPRS, CDMA and EDGE.

“The problem with GPRS and CDMA in comparison to CDPD is we're basically the only ones that really ever took advantage of [CDPD],” he said. “[AT&T Wireless] prioritized our traffic, and we didn't compete with other users on the system.”

Once the migration is complete, public safety will have to contend with circumstances it hasn't encountered before, Bedwell warned. “When there is a crisis in an area, those cell towers get overloaded, and we're going to see the same things in public safety,” he said.

Ray Fastnacht, president of AirLink, which has about 50,000 CDPD customers, suggested concerns over CDPD replacement technologies might be overblown, although problems with the cost of those replacements are certainly real.

“For existing CDPD customers the coverage is not going to be that much different unless they go outside their regions. They'll probably improve coverage,” said Fastnacht.

The improvement comes not in better coverage, but in more coverage, he said.

“There's competition now,” he said. “In the CDPD world, where there were two carriers, you only had one public network [in each market] to take all the business. Now there are at least three [commercial carriers] in every market: typically Sprint, Verizon and AT&T, sometimes T-Mobile. There's almost ubiquitous footprints across the country.”

When listing potential replacement providers, Fastnacht missed a very definite wannabe. Nextel Communications sees the demise of CDPD as a chance to rise in the public sector with a data offering on top of its push-to-talk phones.

Previously, Nextel had never offered CDPD. The opportunity to replace it, though, is huge and difficult to resist.

“When AT&T and Verizon announced the shutdown of their networks, public-safety agencies came to Nextel looking for a replacement solution,” said Jian Khodadad, senior marketing manager for Nextel's OES and embedded solutions group.

The real problem with CDPD replacements, though, is that they cost money, and public agencies are reluctant to fork over the cash when existing gear works reliably.

They also have a hard time asking for funding for new gear — no matter how good or imperative.

“The public is not willing to pay the taxes that would be necessary for public safety to have the newest technology that comes out on the street,” APCO's Nash said. “We're willing to accept that; we're willing to work with older technologies that we're sure work.”

That's why an AirLink upgrade solution that runs $300 to $500 per PC card and between $500 and $1200 per in-vehicle unit can be viewed as a major expense for a cash-strapped public agency budget, even though it would be a tremendous improvement over CDPD and not that expensive in consumer terms.

“Our budget cycles are as long as two to three years, and there are other demands on the budgets. We have to program the money in; it has to come from someplace,” Nash said.

However, an AT&T Wireless spokesman said the carrier has “done a lot to try to migrate people over on this” and added the new technologies provide “significantly faster data speeds and broader national coverage” for about the same price as CDPD. “CDPD covered about 3000 cities and towns across the country. My GPRS and EDGE network is up around 7500,” the spokesman said, adding that some AT&T Wireless offers “pretty much gave most of the equipment for free.”

There are other less disruptive and less expensive software-based options for public-safety agencies anxious to move along — or just to maintain service when CDPD goes away.

For example, NetMotion Wireless created a plug-and-play system that can be downloaded from its Web site and enables any existing mobile data applications to work over wireless networks without customization or modification, said Aaron Burnett, the company's senior marketing director.

“Our software enables organizations of every stripe — public safety, healthcare, enterprise, anyone who's working on mobile computing — to embrace mobile computing or wireless data networking easily and cost-effectively,” said Burnett.

In addition to providing a migration path from CDPD, the software also allows users to view multiple wireless networks as though “they're a single unified network,” he said.

Of the company's 400 customers, about 250 come from the public-safety ranks, he said. AT&T Wireless and Sprint also have purchased NetMotion software in bulk and are “offering it free to organizations transitioning from the CDPD network to their next-generation networks,” Burnett said.

The City of Aurora uses the NetMotion software to slide across different networks seamlessly.

“Once an IP address is established, we use that middleware to roll between our hot spots and GPRS or our hot spots and CDPD,” Bedwell said.

The NetMotion software can even recognize when an Aurora vehicle has become temporarily stationary within a Wi-Fi area, enabling an IP connection to the Wi-Fi backbone so that larger files can be downloaded to the PC within the vehicle, Bedwell said.

Even though his company stands to profit from the demise of CDPD, Burnett said he wasn't a fan of the decision by wireless providers to turn off the service.

“It's all well and good that the carriers decided to turn them off for their own convenience. It's not so hot for public-safety organizations because it left them in the lurch with a huge investment in existing mission-critical applications that now aren't going to work on these next-generation networks,” Burnett said.

With money at the heart of the CDPD issue — and the CDPD sunset extension — all involved seem to be grateful they have more time to figure out what to do next.

“We have a pretty good base of CDPD customers out there, and we've told them that we will support it in the very least until the end of 2005,” said Joe Gardner, staff manager of wireless data services for Alltel. “Our customers are very understanding of that; it gives them time to plan and gives us time to work out whatever the specific solution is they're looking for, and migrate and plan and budget their equipment accordingly.”

AirLink, too, continues to support CDPD and even continues to sell gear; CDPD sales dipped below next-gen wireless for the first time late last year, said Fastnacht.

However, even with the window pried open a little longer, the timing for the migration is awful. Other advanced technology opportunities, including better use of 4.9 GHz wireless spectrum or the even-juicier 700 MHz bandwidth that first responders have been promised by the FCC, are just over the horizon — and seemingly just beyond the window of opportunity.

Right now, wireless technology vendors aren't lining up to build 4.9 GHz gear, and television stations aren't handing over their 700 MHz spectrum after going all-digital as quickly as the government had hoped when it decided to make the spectrum available to public safety.

“I see 700 MHz and 4.9 GHz as the future connectivity for cities like us that can get the frequencies,” said Aurora's Bedwell. “[But] until then, we don't have any options. We have to use the commercial vendors.”

In the meantime, Aurora will use the additional time to shake out some new EDGE technologies that the carriers are offering, Bedwell said.

“We've done some initial testing, and we've had problems with sustaining connectivity in motion and hand-offs between cell tower locations, issues that have already been worked through GPRS and CDMA,” he said. “Like any new network, there's going to be major issues so we have to test it and see if that's going to be a viable option.”

The migration, as stated earlier, will be painful but achievable.