A decade ago, the Association of Public-Safety Communications Officials formally established the Project 25 standard that governs public-safety interoperable digital radio communications in North America. While moving P25 from committee to deployed hardware has been slow in coming, European agencies have more effectively rallied around their own digital radio standard, TETRA.

P25's advocates aren't shy in saying it has taken a while for the standard to catch on, but that is expected to change rapidly over the next few years. While acknowledging that P25 has been “slow gathering momentum,” Don Pfohl, co-director of APCO's Project 25 steering committee, called P25 an “outstanding success.”

“We now have four major [radio] manufacturers that have committed to shipping [P25-compatible] equipment by the end of the year,” he said. “There's been a marked change in this industry. They recognized that Project 25 was the only standard out there that was getting more acceptance all the time. Some of the manufacturers that were against it in the beginning are now coming on board, realizing it is the only game in town now.”

Project 25 was started in 1989 and designed from the outset to be an open standards process to improve spectrum efficiency; allow effective, efficient and reliable intra-agency and inter-agency communications; ensure open competition among multiple vendors; and provide enhanced functionality via equipment and capabilities focused on public-safety needs.

It also was designed to provide an orderly growth path for agencies to migrate from legacy analog equipment into digital systems. Vendors would build equipment to P25-compliant standards, allowing agencies to mix and match equipment rather than being locked into one vendor. Agencies also would benefit by being able to more accurately compare direct features and benefits of both individual radios and entire systems.

Phase I of the project was completed in 1995 and defined the common air interface standard, which specified an FDMA access method, QPSK-C modulation, 9.6 kb/s data rate and a DVSI vocoder using a 12.5 KHz channel.

“There were a couple of non-critical interfaces not included, including a console and inter-system interface, but the basic way radios talk to each other was completed,” Pfohl said.

But the finalization of the P25 standard marked only the beginning of a process that will continue for many years, according to experts. One of those experts, Bill Belt, director of the Telecommunications Industry Association's wireless division, said it takes a while for equipment to be built to a standard once it has been created.

“It takes a lot of money to buy new equipment. There's always a funding problem for communities to upgrade existing analog equipment for interoperable digital systems,” he said. “Radio equipment is very reliable and lasts a long time. Ten years is not an unusually long time for a standard.” TIA has acted as a facilitator in the P25 process, working with APCO and manufacturers to make sure both sides are satisfied and can live with the established standards. “Standards are always designed to be evolving. I hope [P25] is around for many more years as user requirements are evolving,” Belt said.

As P25 was being developed in North America, the European community produced TETRA (terrestrial trunked radio), their own open digital radio standard for public-safety use. “TETRA has been adopted by most countries outside of North America,” said Graham Matthews, managing director of TETRA products vendor Sepura.

“TETRA is in 60 countries worldwide and will have about a million users by the end of the year. Four million users are expected in the next three years. It took a hell of a long time to get the TETRA standard together, but once we got it rolling, it took off.”

All European countries and China have adopted the standard, and contracts for TETRA systems can be found across Africa, Asia, Australia, Europe, the Middle East, South Africa and South America. Because of intellectual property issues surrounding TETRA's GSM technology, the equipment currently is not available within North America.

According to Sepura, about 89 TETRA equipment vendors currently exist, which has created a competitive environment that has benefited end users. “TETRA radios cost well below a thousand dollars each while a [P25 radio] costs anywhere from $5000 to $6000 for a similar product,” said Malcom Ouelch, Sepura's development director.

Another factor that has driven down costs of TETRA-compatible products is the wider market for those products. “TETRA is also suitable for commercial systems. It has a wider appeal to utilities [and] customized solutions,” Matthews said. “TETRA provides trunking with TDMA to make it a high-density solution. You can get a lot of traffic out of it.”

TIA's Belt agreed. “P25 is definitely focused on first responders. There are no commercial applications that I am aware of,” he said.

However, Belt added that P25 systems have proliferated in significant numbers outside of North America. “In mid-2004, there were 660 P25 operational networks in 54 countries worldwide,” he said. “There are large deployments in South America, the Middle East and Eastern Europe, with systems deployed in Russia, India, Australia, and China.”

Pfohl said there are other reasons why P25 radios are more expensive than their TETRA cousins.

“[TETRA] doesn't meet the needs of North America and doesn't meet the needs of a great many public-safety systems,” he said. “A Project 25 system has the same coverage as the analog system it replaces.”

Where TETRA is effective in densely populated areas, Project 25 conventional and trunked systems are more effective in areas where coverage is an issue, Pfohl said. “When you need coverage, Project 25 is much better,” he said. “It's applicable to all the public-safety bands in North America. You can replace an existing [public-safety] analog system with a P25 system and be compatible with legacy equipment.”

There are many places in North America that lack Europe's density, Pfohl said, pointing to his home state of Oregon where he is a communications manager for the state police. “Look at a place like Oregon, [which has] a statewide system with 140 sites,” said Pfohl. “If we tried to put in a lower-power [TETRA] system, it would take over 200 sites and be much more expensive. I think it's true at many parts of the world. Germany is about the same physical size as Montana. Montana has one million people. Germany has ninety million. … In ninety percent of the United States, maybe more of Canada, you don't have the population density to justify anything but Project 25.”

One area where the P25 steering committee would like to see faster progress is the finalization of the Phase II standards, especially intersystem interoperability standards. “In order for systems to grow competitively, we need the intersystem interface,” Pfohl said. “I wouldn't say we are comfortable with the way things are today.”

Also tied into Phase II development are standards for both console interface and fixed station interface. “Once established, you'd be able to competitively bid consoles and base stations,” Pfohl said. “We're not pleased [with the delay]. We have held off making a decision, but if industry can't come to consensus, we may have to force a consensus.”

Belt says that a delay on Phase II shouldn't prevent agencies from acquiring P25 systems. “The standards are designed to be backwards-compatible. There's no reason that an agency couldn't buy a system and expect it to be interoperable with another P25 system. Security, spectrum efficiency and interoperability are all there today. Anyone who buys a P25 system today gets that stuff.”