Project 25 Technology Information Group

Monday, June 25, 2018

Project 25 Technology Information Group

The Project 25 Technology Interest Group (PTIG) offers a single page list summarizing the Top 10 Benefits of Project 25 Communications Technology for Public Safety, Government, and Commercial Users.


Top 10 Benefits of Project 25 (P25) LMR Radio Technology

  1. Public Safety Grade Reliability and Performance
  2. Mature, well defined, P25 Air and Wireline Standardized Interfaces create seamless interoperability to link multiple users, agencies, and systems with local, state-wide, and national coverage, independent of manufacturer.
  3. A Large Installed Base of over 2200 P25 Public Safety, Federal, and Government Systems in the USA (conventional and trunked), offer interoperable roaming and mutual aid beyond jurisdictional boundaries.
  4. Superior security using 256 bit AES for encrypted voice, data, GPS location, and key distribution both over the air (OTAR) and through directly connected key fill devices.
  5. The preferred radio technology for Federal Grant applications
  6. A User-Driven technology that embodies: secure direct mode operation, backward compatibility to legacy analog radios, forward migration to improved spectrum efficiency and cost effective coverage using a variety of P25 system configurations for urban, rural and remote areas using any frequency band or combination of bands (VHF, UHF, 700/800/900 MHz)
  7. A live, active, technology that continues to evolve with new capabilities of wireless and IP network evolution, security upgrades, and test standards.
  8. The reliable, de-facto, choice for mission critical communications during Natural Disasters, Large Sporting and Entertainment events, and Social unrest.
  9. Superior Audio volume and clarity through an advanced P25 vocoder combined with high performance radio designs for specific, high noise, Public Safety environments.
  10. Independent testing for performance and interoperability through labs approved by the Department of Homeland Security CAP program.


A copy of the Document can be downloaded using the link below.

Top 10 Benefits of P25

P25 Standards Update from TIA TR-8 Meetings, Mesa AZ, February 6-8

Andy Davis, TR-8 Chairman

This document highlights TR-8 accomplishments and work in progress for 2018. The document will be updated after every TR-8 face to face meeting occurring in 2018. The filename reflects the date of the latest update. After the first 2018 version, each update will use blue font to indicate the updates.

Completed in 2018:

Air Interfaces

An Addendum to the trunking Control Channel Messages standard was approved for publication

This addendum introduces an "Accessory Sensed Emergency" flag to the emergency alarm message.

Wireline Interfaces
• An addendum to the ISSI Messages and Procedures for Supplementary Data was approved for publication.
This addendum introduces the messages and procedures for Individual Regrouping control across an ISSI/CSSI.





Work in Progress:

Air Interfaces
• A revision to the Conventional Interoperability Test standard is in progress.
This revision corrects editorial errors and makes clarifications on various test procedures but does not add, remove or technically alter tests.
• Creation of a High Signal Strength Intermodulation Rejection Test is in progress.
This test will measure the ability of a P25 or analog conventional FM receiver to reject an unwanted broadband base station signal, thereby preventing degradation to the reception of a desired signal. Performance specifications are expected to follow completion of the measurement method.

Wireline Interfaces
• Group Regrouping for the Trunking ISSI/CSSI Standard is in progress.
This work will enable dispatch equipment connected to Trunking Infrastructures via the ISSI/CSSI to control group regrouping services. Note the control channel messaging for these services has already been standardized.
• A revision of the ISSI Recommended Compliance Assessment Tests bulletin is in progress.
This revision will add recommended interoperability tests for Trunking CSSI applications and add recommended interoperability tests of TDMA operation of the Trunking ISSI and CSSI.
• A new Interoperability test standard for Trunked ISSI Supplementary Data Services is in progress.
This document will provide a standard set of tests for validating interoperability of Supplementary Data Services (Emergency Alarm, Call Alert, etc) operating across a Trunked ISSI.

• Definition of a Link Layer Encryption Security Service is in progress.
This is the first big new technology upgrade for improved Security for all air interfaces of P25. It protects control channel control messages, and hides group and individual IDs.
• An addendum to the Key Fill Interface standard is in progress.
This will enable Key Fill Device (KVL) interface to a KMF, an Authentication Facility and another Key Fill Device

• A revision of the Tier 2 Location Service is in progress.
This revision corrects editorial errors and makes corrections to EXI Encoding examples.

• Definition of 3GPP Mission Critical standard services interworking with TIA Land Mobile Radio standard services is in progress.
This document will describe interworking of features (example; group and individual calls) that are common between 3GPP LTE standards and P25 Trunking, P25 Conventional and Analog Conventional FM LMR standards.


A copy of the report can be downloaded using the link below:

P25 Standards Update February 2018


Join PTIG at IWCE in Orlando March 5-8 2018 to get the latest updates and new information on Project 25 Systems, Case Studies, and the P25 Standards.

See us at the PTIG Booth # 2545

  • View the latest, interoperable, P25 products and services
  • Meet with P25 System administrators and practitioners
  • Get Answers for your P25 questions from Industry technical experts and Consulting Groups

Attend PTIG P25 Panels and Sessions

Note: registration fees required by IWCE to attend these sessions  

P25 Foundations:

Monday March 5th **8:30 AM to 11:30 AM** Room N320GH

Offers an overview of the P25 Standards, Interfaces and applications for P25 Conventional and Trunked technologies.  New P25 standards document releases and future work direction will be covered.  The 2018 Focus will be on ISSI/CSSI interoperability between P25 Systems, New Link Layer Encryption and Key fill device standards, P25 for Emergency Communications, and use of P25 in System Procurement and Upgrades.

P25 User Experience:

Monday March 5th **2:30 PM to 5:30 PM **Room N320GH


Offers Project 25 user experiences and P25 system case studies.  It is structured as a series of presentations from a diverse user group including Federal, State and Local government Systems.  Presentations include P25 system description, its scope, capabilities, agencies served, development history, interoperability achieved, issues resolved, and lessons learned.  Governance structure, and revenue sources will be presented as well as costs for user agency participation.  P25 System interface to Public Safety Broad-band data, and migration will be shared.  

Del Smith, Alaska ALMR (Moderator), Cindy Cast, Miami Dade County FL, Brad Stoddard, State of Michigan, John Richards, State of Maine, Keith LaPlant, United States Coast Guard, Jim Downes, DHS OEC, Chief Lorin Mock, Clay County FL, James Miller, Hamilton County IN, John Valarelli, MTA Police, Long Island NY, Allen Wonder, Washington Metropolitan Area Transit Authority, Washington DC, Stephen Nichols, Project 25 Technology Interest Group


P25 Security: New Standards, Applications, Interoperability:

Wednesday March 7th 4:15 PM to 5:30 PM Room N220E

P25 System Security and Encryption has become increasingly important to protect mission critical communications from unauthorized listeners.  The session will cover: P25 Security Standards updates, enhanced sharing between Key management facilities and devices; and a future new P25 Link Layer Encryption standard.  P25 Authentication and AES encryption applications will be detailed.  Proper planning and coordination is essential to maintain effective communications interoperability.  The panel will address guidelines and best practices for Encryption planning and radio programming applications.


P25 System of the Month

Central Indiana Counties

City of Indianapolis, Marion County, Hamilton County, Madison County

Central Indiana Counties Partner to leverage

cost savings and form a regional interoperable

communications network


The Full Whitepaper including system demographics for the 3 Central Indiana P25 Systems can be down loaded using the link below:

P25 System of the Month: Central Indiana Counties

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The three-county system has realized many great benefits from sharing common infrastructure utilizing the P25 architecture.  Previously all three counties were required to maintain radios in their respective Public Safety Answering Points (PSAPs) and create patches to the respective jurisdictions.  Patching proved problematic and unreliable at best.  A great many of the field units did not have direct communications with the neighboring jurisdictions, especially during large or critical events.  This created a First Responder safety issue, which the counties realized needed to be addressed as soon as practical.

Since the counties have upgraded to P25, the three counties now share talkgroups including public works talkgroups to allow for greater efficiency.  The counties have created several mutual aid (MA) talkgroups that can roam across all systems in the event of a disaster or large-scale event like the Super Bowl.

An additional benefit of the three counties upgrading to P25 is the ability to have interoperable communications with the State of Indiana’s P25 system.  This system is utilized by hundreds of agencies throughout Indiana as well as Federal Public Safety partners.  No longer do officers need to have multiple radios available to communicate to these important partners.

Project 25 Technology Interest Group Releases New Whitepaper:

Project 25 Radio Authentication

The paper was authored by:

Jim Holthaus, Vice President, Chief Technical Officer, BK Technologies

Project 25 radio standards now provide a method of authenticating subscriber radios for operation on P25 trunked radio systems.  This paper explores the need for and functionality of P25 Link Layer Authentication services on trunked radio systems.

For decades, public safety communications system operators were protected from unauthorized access through the restrictions that equipment manufacturers placed on radio programming equipment.  So even if an unauthorized individual had radio equipment and programming software, without the so called ‘system key’, programming a radio for an individual radio system was not possible.  In general, this level of protection works quite well for many public safety agencies.  However, the use of the system key is only as reliable as the methods used to protect unauthorized access to such a key. 

As the technological abilities of those wishing to steal service or disrupt public safety communications systems expand, additional measures to protect unauthorized access to public safety communications systems are required.

Public Safety and government radio users, through the Project 25 Standards process have requested inclusion of additional measures to prohibit unauthorized access to P25 systems.  The Project 25 standard provides this protection through the use of authentication technology.  The Project 25 standard defines a challenge/response system that allows the radio system and/or subscriber radio to authenticate itself before service is granted. 

The full whitepaper on P25 Link Layer Authentication can be found using the link below:


Project 25 Radio Authentication





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