Project 25 Technology Information Group

Friday, July 20, 2018

Project 25 Technology Information Group

Mission Critical Magazine recently published a new article on the P25 ISSI and CSSI

The Importance of P25 Wireline Interfaces ISSI and CSSI

Mike Schools, Catalyst CommunicationsTechnologies’ Vice President of Engineering

Below is an excerpt from the Mission Critical Magazine article:


"Open standards offer benefits that are difficult to overstate: freedom of choice for customers; lower overall cost of development, which is ultimately paid for by customers; vendor confidence that development can be re-used and refined; and freedom for both customers and vendors to focus on real issues including innovations that reduce costs and enhance productivity.  The results of our process check indicate that P25 standards are off to a great start, but require more investment, further refinement and full adoption.  These potential benefits materialize only if the standard is adopted extensively, not only by manufacturers but also by customers and the consultants who advise them. In the consumer world you can see many examples of standards that thrived because customers invested in products that used them. VHS succeeded over Betamax not because it was a superior technology, but because customers bought and invested in it first. Blu-ray won out over HD-DVD for more complex reasons, but ultimately customers only embraced Blu-ray. Cutting-edge technologies in their day, eventually both became reliable and inexpensive. But customer buy-in and acceptance was critical to continued investment and additional refinements by industry. No matter what the technical potential of a solution, adoption and economics drive its development and maturation.  Every technical person in every industry I’ve ever worked in believes at some level that their industry or organization has special requirements that just aren’t like anyone else’s and that they need a custom, special purpose solution. Technology is expensive to build, maintain and support.  Simply put, accommodating proprietary interfaces is more expensive than using one standard interface. Adoption enables our industry to expand its available offerings by leveraging the combined efforts of every vendor in the industry. That would mean that the wireline P25 standards — CSSI, ISSI and the Fixed Station Interface (FSI) — should be the only interfaces used for core P25 wireline communications, regardless of what vendor supplies the individual pieces of the subsystem, though manufacturers could continue to differentiate using proprietary extensions to the standards".



The full article can be found on the Mission Critical Magazine  link below.

The Project 25 Technology Interest Group (PTIG) held it’s Annual Meeting in conjunction with the APCO International Conference in Washington on August 16th. At that meeting, a Board of Directors and Officers were elected. A number of New Board members were elected from the Public Safety Radio User Community to fill vacancies created as previous members moved on. These include:

  • George Crouch who is the Public Safety Communications and Emergency Operations Administrator for the South Carolina Department of Administration, Division of Technology Operations. Mr. Crouch’s duties include administration of South Carolina’s Statewide 800 MHz Public Safety Radio System (Palmetto 800), communications interoperability planning, state coordinator for ESF-2 (Communications), and contract manager for the state’s communications. Mr. Crouch is the Co-Chair of the Project 25 Steering Committee
  • Cindy Cast who serves as the Radio Systems Manager in the Information Technology Service Department, Radio Communication Services Division of Miami-Dade County, . She is responsible for activities associated with the management, maintenance, repair, and uninterrupted operation of the telecommunication radio systems, including the 800 MHz/700 MHz P25 trunked simulcast radio systems. The systems serve over 30,000 radio users.
  • John Richards who is the Director of Radio Services for the State of Maine. He has been in that role since December of 2012. He manages Maine’s new P25 Public Safety Radio system. Previously he was Operations Manager for Yankee Communications in Benton Maine, a position he held for over 18 years.
  • Eric Linsley who is employed by Mobile County, Alabama, Commission as the Director of Public Safety Communications. Eric is the Department Head in charge of all Mobile County Commission Electronic Systems. Eric is Chairman of the Region 1, Alabama 700 MHz & 800 MHz Planning Committee and local frequency advisor for Alabama.
  • Tom Bowen who is the P25 Radio Network Administrator for Floyd County Government in Rome, Georgia. He is the Radio System Administrator for 2000 users on an APCO P25 based Simulcast network with 10 tower sites. It is a Public Safety network with the addition of public works and private agencies. Mr. Bowen also assists with Emergency Management rescue, CERT and amateur radio volunteers.

Other Radio Users returning to the PTIG Board include: Del Smith- Alaska ALMR, Brad Stoddard-State of Michigan; Brandon Diemer-BLM NIFC, Eric Davies- DHS; Karl Larson-City of Portland; Dean Hane MACC-911; and Jim Junkins-Harrisonburg/Rockingham VA.

The PTIG Board also includes returning Commercial Members including: Andy Davis-Motorola Solutions and TIA TR-8 Chair; Chris Lougee ICOM America and TIA PRS Chair, Jim Holthaus RELM and Chair TIA TR8.25 Compliance Assessment; James Reid-Harris; Cheryl Giggetts-AECOM; Neil Horden-Federal Engineering; Roy McClellan- Airbus DSC; Doug Chapman-Etherstack; Robin Grier-Catalyst; Sanjay Patel-IDA.

The PTIG Slate of Officers was also nominated and elected at the Annual Meeting. Chairman: Del Smith, Vice Chairman: Jim Holthaus, Treasurer: Chris Lougee, Secretary: Andy Davis. Stephen Nichols was appointed to continue as Executive Director for the non-profit organization.

The Project 25 Technology Interest Group has recognized the Miami Dade County P25 System as "P25 System of the Month". 

The system of the month is a new feature for the WEB site.

If you are interested is submitting a P25 system for consideration, please reply to This email address is being protected from spambots. You need JavaScript enabled to view it. 

 P25 System of the Month Miami Dade pdf for upload


Project 25 Technology Interest Group


P25 System of the Month


Miami-Dade County FL





Cindy Cast, Radio Systems Manager

Miami-Dade County has one of the nation’s largest 800 MHz/700 MHz. Project 25 (FDMA phase I) radio telecommunications systems. The Harris P25 system supports both government and Public Safety operations for multiple agencies including:

  • Miami-Dade Police Department
  • Miami-Dade Fire Rescue
  • Miami-Dade Corrections and Rehabilitation Department
  • Miami-Dade Transit
  • Miami-Dade Public Works and Waste Management
  • Miami-Dade Water and Sewer
  • Miami-Dade Airports
  • Miami-Dade Seaport
  • Miami-Dade County Public Schools
  • 29 Municipalities in the region

In addition to these local agencies, numerous state, federal, and tribal agencies depend on this P25 system for day-to-day communication among first responders, and for coordinated multi-agency response to natural disasters and special events. The systems are used daily for regular operational work within the County, the International Airport, the Port of Miami (Cruises and Cargo Ships), and day-to-day events in this large metropolitan area. They are used during large sporting events such as in the Sun Life Stadium for the NFL Miami Dolphins Football games and in the Marlins Park for the MLB Miami Marlins Baseball games.

The P25 radio systems cover the entire Miami-Dade County geographical area and service over 95 agencies/departments with over 30,000 active radio devices. On a monthly basis there are over 5 million transmissions processed by the radio systems. Miami-Dade County self maintains the radio administration, infrastructure, terminal unit repairs, installations, and interoperability with agencies. The Radio Communications Services Division has 51 employees dedicated to support these functions.


On August 6, 2004, the Federal Communications Commission (FCC) issued a report and order to modify its rules governing the 800 MHz band stating that public safety and other radios systems occupying the 800 MHz band were experiencing radio frequency interference as a result of the growth in adjacent commercial bands. The order required its users, including Miami-Dade County, to reconfigure operations by engaging in a frequency swap known as rebanding. On January 28, 2010 the Board of County Commissioners (Board) approved a Resolution waiving the formal bid procedures to authorize the execution of a settlement agreement with Nextel South Corporation and a purchase agreement with Harris Corporation to address the FCC mandate. The rebanding effort as required by FCC and the ensuing agreements provided the County with a change from the EDACS proprietary trunked technology to a P25 open source, state of the art radio communications systems. The project was completed in two tasks.


The first task of this project was successfully completed by the end of December 2012 which consisted of a 20-channel P25 trunked simulcast system. The users of this system consist of non-law enforcement agencies and departments (i.e. OEM, Fire Rescue, Schools, and Transit). As part of this task, a Harris P25 Inter RF Subsystem Interface (ISSI) was configured to work with a Motorola P25 ISSI connected to a County owned 450 MHz conventional system. These ISSI connections provide access to additional radios to connect to the system. The second task of this project was completed by November 2014 which consisted of a P25 20-channel P25 trunked simulcast system and several mutli-site systems. These systems have law-enforcement agencies and departments.

Aggressive Schedule Met On-Time

This project was completed on schedule even with the magnitude and complexity of mobilizing thousands of users across Miami-Dade County. It consisted of coordinating and planning the installation of antennas, support systems, upgrading electrical systems, physically reprogramming an estimated 30,000 radios, training users and having to resolve a multitude of challenges along the way. This project impacted the entire base of law enforcement and general government agencies which were transitioned to the new P25 infrastructure in a period of less than four years since the resolution was approved in January 2010.

Success Factors

Rigorous planning and commitment from all agencies/vendors working as a team, resulted in a successful cut-over.  Extensive user training was one of the critical factors leading up to the success of the project. There are distinct differences with the audio characteristics and functionality of an analog and a digital system. To address this, multiple types of training sessions were provided (i.e. one-on-one, group, roll-call meetings, and overview meetings) along with a 24/7 call center for questions (during and after cutover) and a quick-reference training pamphlets distributed to the users.


Users of the new P25 systems have expressed a high level of satisfaction. The systems are currently successfully processing millions of calls each month.

To see how your P25 System can be nominated as a P25 System of the Month


Stephen Nichols

Director Project 25 Technology Interest Group

This email address is being protected from spambots. You need JavaScript enabled to view it.

Arlington, VA (August 18, 2015) – The Project 25 Technology Interest Group (PTIG), and The Telecommunications Industry Association (TIA), the leading association representing the manufacturers and suppliers of high-tech communications networks, announced a Friendship Agreement to facilitate communication regarding standards development for interoperable radio communications systems and equipment for public safety.


A video of the signing Interview with Del Smith PTIG chairman, Steve Nichols PTIG Director, and Stephanie Montgomery Vice President of Technology and Standards for TIA can be viewed at: or by clicking this   link 




Del Smith, Operations Manager for Alaska Land Mobile Radio Communications and Chairman of Project 25 Technology Interest Group, said: “P25 technology has been very instrumental in the advances in public safety communications and interoperability we have seen over the years. The PTIG was formed to further this technology by educating people about the importance of the P25 standard. By providing a forum for vendors and the public safety communications community, PTIG will continue to inform TIA’s technical work to further build on and improve the P25 standard.”



Steve Nichols, Director of Project 25 Technology Interest Group, said: “P25 was created in a way that allows a very flexible type of deployment – from small municipalities to large statewide systems – because it was based on users’ needs. PTIG works with TIA to communicate this technology to the users – the patrol officers and the firefighters – so they can understand and provide input into the technical process, as well as to promote the use of the P25 technologies to advance interoperable public safety communications. We look forward to continuing this work with TIA to expand and improve this important technology.”



Stephanie Montgomery, Vice President of Technology and Standards for TIA, said: “Today, the P25 standard for interoperable public safety communications is a robust technology solution deployed in more than 80 countries. Part of what makes this standard a success is that the technical work is informed by the user community and PTIG. This input and feedback allows TIA to address the specific needs of public safety communications professionals and advance the technology. TIA and PTIG’s friendship agreement recognizes and encourages this invaluable information sharing relationship to further develop and improve this critical communications standard.”



The Project 25 Technology Interest Group (PTIG) is a non profit organization made up of individuals and organizations who share the mutual interest of advancing the refinement, development, deployment, and applications of the digital communications technology represented by Project 25 industry standards.. The P25 standard was developed by state, local and federal representatives and is governed by TIA’s Mobile and Personal Private Radio Standards Engineering Committee (TR-8). Radio equipment that demonstrates compliance with the P25 standard is able to meet a set of minimum requirements for public safety needs. Public safety agencies around the world depend on P25 for their mission critical communications.



As an American National Standards Institute-accredited standard development organization, TIA develops design and manufacturing standards for digital voice and data communications systems suited for public safety and first responder applications. Specifically, TIA has developed a series of standards (TIA-102) for Project 25 (P25), which enables interoperability among multiple manufacturers’ products designed to the P25 standard.





PTIG Website Events Calendar Updated for August 2015


Check out the details posted for the PTIG Annual Meeting and Elections; and for P25 Topics featured at APCO 2015. 

They are both coming up next week August 16 - 19 in Washington DC. 







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