Project 25 Technology Information Group

Wednesday, April 21, 2021

Project 25 Technology Information Group

P25 Sharing = Cost Savings for Stonington CT.

Stonington CT. Police are the Latest P25 Sharing=Cost Savings Success story. Full details were recently published in an article in “The Day” newspaper by Lindsay Boyle.

A link to this article is below.


In their agreement with the State Department of Emergency Services and Public Protection, Stonington spent $1.3 million to build a communications tower and purchase P25 radios. It is estimated that their Cost savings over having to build a stand-alone system was $3.1 million.

In addition to the cost savings, several improvements to the agency’s communications were realized. They now have coverage in a historic local dead spot with their new tower and they have interoperability with the Connecticut State Police and other municipal P25 systems for mutual aid using towers across the State. The interoperability for any state agency, as well as their neighbors improved tremendously.  Example: they – for the first time ever – shared a talkgroup and were able to communicate directly with their neighboring community.


Groton CT recently joined the Connecticut statewide system and Norwich is planning to join soon giving improved communications through P25 interoperability in the region. Many other municipalities — including ones in Rhode Island and New York are considering signing on.   The State of Connecticut is working on interoperability with communities in RI and a P25 System to System ISSI connection with the Metropolitan Transit Authority in NY (MTA has subscriber units already using the system)

PTIG Publishes Updated P25 Trunking Systems List May 2019

The Project 25 Technology Interest Group (PTIG) has published an updated P25 Trunking Systems List. There are currently 1017 P25 Trunking Systems identified for inclusion on the list. The list covers known systems in the US, Canada, Australia, New Zealand, and the UK. The list is organized by State and Nation. Thanks to Ken Brown for his research efforts to update this list.  Please send any additions/corrections to Steve Nichols This email address is being protected from spambots. You need JavaScript enabled to view it.


The full list can be downloaded using the link below:

P25 Trunking Systems List May 2019


There were 194 New P25 Trunking Systems Identified since the list was last published in 2017. Other major trends include a strong migration from P25 Phase 1 to P25 Phase 2 Systems. P25 Phase 1 Systems are down from 728 systems to 652 Systems while Phase 2 systems are up from 188 to 364 known systems. In addition, 93 P25 Systems have been merged or consolidated into larger Regional or State-wide P25 systems and are no longer listed as stand-alone systems. The net total with consolidations removed is up 101 systems from the 2017 list.

P25 Conventional Systems are found on a separate list on the PTIG website. There are 1334 Conventional Systems on that list. The grand total of P25 Systems both Conventional and Trunking is 2351.

P25 trunking List Changes 2017 2019

The P25 Trunking System List Includes System Name, P25 Phase 1 or P25 Phase 2, Primary User designation, Statewide System Designation, and the Frequency Band in use.

Public Safety remains the primary user type with DoD and Federal Agencies being the other primary user Groups. Additional P25 systems were recognized for Public Works, Utilities, Corrections (non Federal), Business, Airport/Transportation, and Universities. There are 37 Statewide P25 Trunking Systems recognized.

P25 Trunking User Type Chart

Frequency Bands in use remain dominated by 800 MHz, 700 MHz and UHF LO (380-420 MHz).

P25 Trunking Systems Frequency Bands

The Project 25 Technology Interest Group (PTIG) is pleased to publish a new Best Practices for Planning and Implementation of P25 Inter-RF Subsystem Interface (ISSI) and Console Subsystem Interface (CSSI): Volume I. This document is a result of an extensive collaborative effort of the Federal Partnership for Interoperable Communications (FPIC) ISSI/CSSI Focus Group supported by supported by the Department of Homeland Security Cybersecurity and Infrastructure Security Agency Emergency Communications Division.


Executive Summary

Project 25’s (P25) open standards define features and functions and the interfaces of P25-compliant radio systems. Two of these interfaces, the Inter-RF Subsystem Interface (ISSI) and the Console Subsystem Interface (CSSI), are designed to enhance the operability and interoperability of new or existing land mobile radio systems.

ISSI technology allows for multiple radio core systems or RF subsystems to link together and form larger wide-area networks, supporting the “system-of-systems” concept. The CSSI interface provides interoperability among multiple dispatch console vendors and system infrastructure manufacturers, which enables third party P25 console options.

Given increased interest in both ISSI and CSSI technology, the Federal Partnership for Interoperable Communications, supported by the Department of Homeland Security Cybersecurity and Infrastructure Security Agency Emergency Communications Division, established the ISSI/CSSI User Working Group (comprised of users and manufacturers) and the Focus Group (users only) to explore the ISSI/CSSI technology environment including but not limited to, successfully connecting single and multiple manufacturer ISSI or CSSI systems, collecting user and manufacturer implementation procedures, troubleshooting methods, and identifying best practices.

This document’s purpose is to outline components for practitioners to consider when planning for and implementing an ISSI or CSSI implementation. The high-level components are rooted in best practices observed during all project phases by local, county, regional, and state agencies implementing ISSI/CSSI and are provided as a resource for others in the community who may be contemplating or implementing ISSI/CSSI. The six components are listed below; the first two are addressed in this volume while the other four will be addressed in a future volume.

  • Pre-Planning
  • Partnerships and Governance
  • Stakeholders
  • Technology
  • Policies
  • Thinking Ahead

The Full document can be downloaded using the link Below:

P25 ISSI/CSSI Best Practices Guide

It can also be accessed using the DHS Werbsite link below:



The Project 25 Technology Interest Group (PTIG) offered two new P25 Informational PPT presentations at IWCE 2019. 

Descriptions of the presentations and links for download are found below.


P25 New Products for 2019

As part of the PTIG P25 for the Future Panel at IWCE 2019, Cheryl Giggetts of CTA Consultants, offered a snapshot view of the latest P25 New Products and Services for 2019. She brought the technology to life with a dynamic summary of the benefits of each new offering.

Thanks to all the PTIG member companies who participated: Intertalk, Compliance Testing, PCTEL, Harris, ICOM, Catalyst, Telex, JVC Kenwood, Unications, Codan, Futurecom, Locus, Valid8, Avtec, Etherstack

The full PPT can be downloaded using the link below:

P25 New Products IWCE 2019


P25 Testing 

A New “P25 Testing in Development” table was offered at the PTIG Booth at IWCE 2019.

It featured a laptop with rolling Kiosk PPT showing new P25 testing products and services in development. 

Participating PTIG members: Valid8, PCTEL, Etherstack, Compliance Testing, Locus USA.


  • Valid 8 P25 ISSI/CSSI Testing: Multi Platform Multi form factor using VPN, Customer Lab or Valid8 lab
  • Compliance Testing:P25 ISSI InteroperbilityTesting, Installed FNE’s tested via VPN by an A2LA accredited lab. CTL Lab, Manufacturer Lab City or Agency Site can be test sites.
  • PCTEL: Testing Indoor Public Safety Communications for P25 Systems. Grid based on NFPA, IFC, AHJ regulations
  • Locus USA: P25 Over-the Air Radio Diagnostics for large coverage Deployments. Comprehensive report on radio alignment for each individual radio ID.
  • Etherstack: P25 Off –Air Monitor. Non-intrusive, Bi-directional P25, Channel Observation, P25 Air Interface Testing, P25 Interoperability Verification, Real-time Maintenance and Diagnostics

The full PPT can be downloaded using the link below:

P25 Testing in Development IWCE 2019



The Project 25 Technology Interest Group (PTIG) presented two informative P25 Panels at the recent IWCE Conference. 

Below you will find a description of the panels and links to download the PPT presentations that were offered.


P25 for the Future: New Products, Applications, Interoperability and Security

This was possibly the best PTIG IWCE panel in the last 4 years. The room was standing room only with 110+ attendees and most stayed through the entire 3 hour presentation. Thanks to all of our presenters who did an excellent job.

Download the full PPT below in two parts:

P25 for the Future IWCE 2019 PPT (Part #1)

P25 for the Future IWCE 2019 PPT (Part #2)


Steve Nichols, PTIG Executive Director, began with a PTIG Overview, P25 Website resources, and P25 Documents available. P25 Benefits slides were presented answering “Why are so many PTT users Choosing P25?”

Dominick Arcuri (Televate) then set the stage with an excellent overview of the Standards Process, P25 Interoperability Interfaces and P25 Configurations

Andy Davis, TIA TR-8 Chairman, (Motorola Solutions) followed with his traditional standards Update for the TIA TR-8 Standards Meetings and then detailed the work being done by the TIA/ATIS LMR LTE Joint Project Committee on Interworking between LTE Mission Critical and LMR Services.

Jeremy Elder (Harris) gave a good update of Link Layer Encryption Standards in development and how they will affect existing systems, new users and legacy users. He added the latest update on P25 Key Fill Device standards and Important User Considerations for their application.

Alan Massie (FBI) then took the Encryption topic to reality with a good overview of the FBI System, NLECC SLN Interoperability resources and best practices for SLN assignments.

Keith LaPlant (USCG) followed with an detailed description of the US Coast Guard’s Rescue 21 System including it’s key features, capabilities, coverage and most important, how to work with the USCG for P25 Interoperablity.

Justin Evans (Montgomery County TX ) and Greg Jurrens (Harris County TX) teamed to present an excellent update on ISSI/CSSI Interoperability. They began with a compelling real world example of their experience with ISSI/CSSI Interoperability in Texas. Then added an update on the ongoing work, survey results and P25 resource documents from the ISSI/CSSI User Focus group sponsored by FPIC. PTIG will continue to publish public documents from this key working group.

Cindy Cast, PTIG Chairman, (Miami Dade County), Del Smith (Alaska ALMR), and Greg Jurrens (harris County TX) delivered the next section focused on the ways P25 Sharing can result in Cost Savings for User Agencies. Profiles with specific savings figures were included for a variety of P25 Systems and agencies decisions contrasting the cost to stand alone or share P25 Infrastructure. This will be a great building block for a future whitepaper.

Jim Holthaus (BK Technologies) and Robin Grier (Catalyst) then presented a solid briefing on the use of P25 Connections for Emergency Communications and Mutual Aid. This profiled the nationwide footprint of over 2200 P25 systems available, use of the NIFOG, 37 statewide systems and their Shared Interop talk group plans, and Interworking and Interoperability with P25 LMR and LTE for Emergency Communications, Incident Command and Mutual Aid.

Cheryl Giggetts (CTA Consultants), then offered a snapshot view of the latest P25 New Products and Services for 2019. She brought the technology to life with a dynamic summary of the benefits of each new offering. Thanks to all the PTIG member companies who participated in this section: Intertalk, Compliance Testing, PCTEL, Harris, ICOM, Catalyst, Telex, JVC Kenwood, Unications, Codan, Futurecom, Locus, Valid8, Avtec, Etherstack

Jim Downes: P25 Steering Committee Chairman, closed the panel session with a great overview of Project 25 testing and Compliance. This included the importance of sustainment for P25 LMR systems, a definition of the various levels of Compliance Testing, the CAP program, and the new Non CAP ISSI Interoperability test template.


Project 25 with LTE: Mission Critical PTT Interworking Standards in Development

This timely topic attracted a good audience of 50+ attendees with interest in the future Interworking of PTT between P25 LMR and LTE. Thanks to the panel who did a well-researched update and presentation.

Download the full PPT below:

P25 with LTE Interworking PPT IWCE 2019


Cindy Cast, PTIG Chairman,(Miami Dade County) began with the Overview and User perspective. This included a good definition of the technologies and systems in use today for P25 and LTE. The critical metrics that are used to define LMR systems were presented and a future view was detailed with expectations and requirements from the User perspective for future Interworking.

Jeremy Elder(Harris) then offered an interesting Business Model defining suggested Deployment Models for P25 and LTE MCPTT interworking. A General Model, Carrier-Centric Model, Cloud Deployment Model, and On-Premise Deployment Model were defined with the benefits and challenges of each approach.

Andy Davis,TIA TR-8 Chairman (Motorola Solutions) closed the panel with a detailed update of the work by the ATIS/TIA Joint LMR LTE Joint Project Committee. This included the background, Issue Statement, Current Work, and a functional Model showing the LMR to LTE Interface as defined by the committee. The current definition Document in development was presented with a philosophy and goals for the report that is due in June of 2019.





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