Office of Justice Programs n Innovation • Partnerships • Safer Neighborhoods n www.ojp.usdoj.gov

The Wisconsin State Patrol, which oversees traffic 

incidents, statewide voice communications and 

mobile communications networks, has devoted several years to developing a strategy for adopting the 

Project 25 radio interoperability standards.

Project 25 refers to a suite of standards for digital, 

two-way wireless communications products. A 

committee of manufacturers, public safety agencies, and state and federal communications professionals launched Project 25 in 1989 to provide 

detailed standards for interoperable radios.

How Law Enforcement Can Migrate to

P25 Standards

P25-compliant products are being increasingly 

adopted in today’s digital age. The radios can communicate in analog mode with legacy radios and in 

either digital or analog mode with other P25 radios. 

P25-compliant products allow for a high degree 

of equipment interoperability and economies of 

scale. Specifically, P25 products can be upgraded 

gradually, achieving interoperability and security, 

encouraging committed manufacturers to provide 

compliant products, fostering competition and 

achieving cost-effective communications.

Converting From Analog to Digital: P25 Limits

Many agencies cannot afford to buy and set up a 

P25-compliant system outright. Estimated costs 

can easily run in the millions of dollars and entail 

dedicated engineering support. In addition, various 

radio manufacturers interpret the P25 standards differently and use different words to refer to identical 

ideas, creating confusion for law enforcement agencies that want to make the switch.

New technology and decreasing production costs 

now allow agencies to switch from analog to P25-

compliant products gradually without incurring the 

astronomical costs currently associated with making a full upgrade. In this way, law enforcement 

agencies can transition from analog to full P25 

digital as funding and time allow.

Making the Switch to P25

The Wisconsin State Patrol ran a four-site pilot 

program that created P25 capabilities across the 

network. For this pilot, the agency tested a P25 

channel controller, a new product that converts 

conventional analog repeaters into P25 repeaters 

across multiple sites and in support of multiple 

frequencies.

Several companies provided analog repeaters at 

test sites. Mobile and portable radio companies 

were also involved, assessing the compatibility of 

their equipment with the central system.

The Wisconsin State Patrol and other participants 

ran into various glitches related to programming. 

However, the pilot experience showed the extent 

of the cooperation needed between the vendor and 

law enforcement communities to achieve the best 

and most cost-effective solution. Other law enforcement agencies planning to upgrade their systems 

may benefit from Wisconsin’s experience and the 

various issues that surfaced during the pilot. 

Benefits of Migrating to P25

Law enforcement agencies considering adoption 

of P25 may benefit from reduced technology and 

labor costs. Agencies can convert existing analog 

channels to P25 digital signaling without changing 

base stations.

NCJ 229517

APRIL 2010

U.S. Department of Justice

Office of Justice Programs

National Institute of Justice

Toward Criminal Justice Solutions

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short

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Wisconsin State Patrol Tests New 

Path to Radio Interoperability
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The emergence of the P25 standard and related 

products over the past two decades has allowed 

many agencies to upgrade their antiquated systems and achieve interoperability. With increased 

competition in the marketplace, agencies will see 

decreased costs for the use of P25 technology. For 

agencies considering converting to P25, there are 

benefits and indirect cost savings to be gained, 

including the ability to use existing equipment and, 

thus, avoid the need for added training. 

A strong partnership between law enforcement 

agencies and product vendors is necessary 

throughout the product development and installation phases. In addition, the law enforcement 

community must develop a standard lexicon of 

P25 terminology for product vendors. Thus, its 

continued role in the changing P25 standards 

landscape remains an integral one.

Pitfalls and Lessons Learned

The Wisconsin State Patrol P25 pilot exposed several 

pitfalls that agencies should consider when migrating to P25, namely the varying terminology, settings and software provided by the manufacturers. 

Previously, vendors have interpreted the P25 standards in their own way, without any guidance from 

This document is not intended to create, does not create, and may not be relied upon to create any rights, substantive or procedural, enforceable at law by any party in any matter civil or criminal. Opinions or points of view expressed in this document represent 

a consensus of the authors and do not necessarily represent the official position or policies of the U.S. Department of Justice. The 

products and manufacturers discussed in this document are presented for informational purposes only and do not constitute product approval or endorsement by the U.S. Department of Justice.

*NCJ~229517*

the law enforcement community. Through this pilot 

experience, practitioners and vendors alike gained a 

better understanding of the outstanding issues and 

identified ways to improve the implementation of 

P25-compliant technology.

For More Information

■ NIJ’s Communications Technology 

(CommTech) Web Site:

http://www.ojp.usdoj.gov/nij/topics/technology/

communication/welcome.htm

■ Wisconsin State Patrol

http://www.dot.wisconsin.gov/statepatrol

■ Project 25 Technology Interest Group

http://www.project25.org

■ Wisconsin State Interoperability Council

http://siec.wi.gov

Note

Jackson, D. "Raytheon JPS P25 Migration Path 

Demonstrated in Wisconsin," Mobile Radio 

Technology (November 8, 2007). Available 

online at http://urgentcomm.com/project25/news/

raytheon_p25_wisconsin_110807/index.html.