Project 25 Technology Information Group

Monday, June 25, 2018

Project 25 Technology Information Group

P25 Standards Update from the TIA TR-8 Meetings San Diego Oct 18-19

Andy Davis, Chairman TIA TR-8

This document highlights TR-8 accomplishments and work in progress for 2017.  The document will be updated after every TR-8 face to face meeting occurring in 2017.  After the first 2017 version, each update will use blue font to indicate the updates.



The full report can be accessed using the link below

Updates from the October Meeting:

Completed in 2017:

Air Interfaces

  • An addendum to the Trunking Control Channel Messages standard was approved for publication.

     This addendum introduces a “Vehicle Sensed Emergency” flag to the Emergency Alarm message.

  • An addendum to the Trunking Control Channel Messages standard was approved for ballot.

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 ballot.

This addendum introduces the messages and procedures for Individual Regrouping control across an ISSI/CSSI.



  • A revision of the Location Services Overview bulletin was approved for publication.

This revision aligns the content of the Overview document with the content of the Tier 1 and Tier 2 Location Service Specifications.


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. 



Project 25 Technology Interest Group Releases New Whitepaper:

Project 25 Trunking Control Channels

The paper was authored by:

Dominick Arcuri: DVA Consulting

Andy Davis: Chairman TIA TR-8, Senior Resource Manager-Motorola Solutions

The New Project 25 Technology Interest Group Whitepaper defines the use and benefits of the current P25 Frequency Division Multiple Access (FDMA) Trunking Control Channel used in most P25 Trunking Systems today as well as application and benefits of the new, recently released, P25 Time Division Multiple Access (TDMA) Trunking Control Channel.  Planning and User Interoperability considerations required for transition from FDMA to TDMA P25 Trunking Control Channels are also covered.  These include a thorough inventory of the subscriber base and roaming requirements for all agencies supported by the system, including visiting radios from interoperability and roaming partners. 

The P25 suite of standards is evolving and continuing to grow as technology and user requirements evolve.  The standardization of the TDMA control channel will enable multiple manufacturers to support this capability with interoperable equipment.  Additionally, the TDMA control channel will provide another option for system managers and user agencies to effectively support their users and to improve the spectrum efficiency of their network both low density and high density situations. 

A copy of the Full whitepaper can be found on the Project 25 Technology Interest Group Website using the following link:


Whitepaper: P25 Trunking Control Channels



A P25 trunked system can be deployed with either FDMA or TDMA traffic channels or a mixture of FDMA and TDMA traffic channels.  The FDMA Common Air Interface (CAI) is designed to provide 12.5 kHz spectral efficiency and meet FCC (Federal Communications Commission) narrow-banding requirements, while the TDMA CAI is designed to provide 6.25 kHz “equivalent” spectral efficiency by providing two virtual channels within a 12.5 kHz channel.  For TDMA, the two virtual channels are commonly referred to as “TDMA slots”.  When a 12.5 kHz channel is operating in TDMA mode, the infrastructure is using both slots for outbound signaling.  Depending on how the TDMA channel is being used, radios are instructed to use one or the other slot for inbound signaling (radio to infrastructure) and radios will listen to one or both slots for outbound signaling (infrastructure to radio).

Prior to the development of the TDMA control channel, both FDMA and TDMA trunking traffic channels utilized an FDMA 12.5 kHz control channel.  A new addition to the P25 suite of standards defines a TDMA control channel for P25 trunking operation.  Similar to the FDMA trunking control channel, the TDMA control channel includes an inbound (radio to infrastructure) channel which is used for individual or group service requests for voice, data or supplementary service.  It also includes an outbound (infrastructure to radio) channel which broadcasts system information, control signaling, and provides call assignments.

The Project 25 Technology Interest Group is pleased to welcome ACD Telecom as our newest PTIG member.

Founded in March of 1998, ACD Telecom, an engineering and management communications consulting firm specializing in Public Safety Communications.  ACD Telecom’s headquarters are in Lake Mary, Florida with two other offices located in Pennsylvania and California. 

ACD Telecom has been involved and active in P25 since its inception in 1989.  Ali Shahnami was a former APCO Headquarters' Director of the Frequency Coordination Department where he was involved and active within P25/TIA committees such as: Encryption Selection, Compatibility and Interoperability between various manufacturers (lockdown committee) and TSB88 documents development. 

As a natural progression from working with public safety agencies nationwide it made sense to retain those core ideals and capabilities in Public Safety Communications.  ACD Telecom has strong background, knowledge and experience in P25 system technology, FCC/FAA rules & regulations, spectrum management and licensing, project management, in-building/on-street coverage testing, RFP development and negotiation, and needs assessment.

ACD Telecom Business Development Contact 

Name: Ali Shahnami  

Title: Vice President

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

Phone: 407-333-2300

Company WEB site:

Mailing Address: 103 Commerce Street, Suite 180 Lake Mary, FL 32746

PTIG publishes a presentation of New P25 Products and Service for 2017


Project 25 has a vibrant ecosystem of users, manufacturers, consultants, and government support with a continuous flow of new products and services that leverage the latest technology.

This Power-point presentation highlights the latest New P25 Products and Services from the members of the Project 25 Technology Interest Group (PTIG).  Categories  include P25 Mobiles and Portables, Pagers, Rpeaters, System Elements and Capabilities, Vocoder Devices and Services. 

The slides describe whats new about the product or service, user needs met, benefits to Public Safety, and the relevance of the new product or service to the existing market.  The products and services are presented in an informational news format.

Some Questions answered by the presentation include: 

What potential sources and contacts exist today for Project 25 Products and Services?

What are the latest new P25 Products and Services that have been just released?

How do these new product and service offerings benefit Public Safety and Public Safety users.


A link to the Powerpoint Presentation is below


New P25 Products and Services for 2017



Project 25 Technology Interest Group (PTIG) Elects a New Board of Directors and Officers.

The Project 25 Technology Interest Group (PTIG) held it’s Annual Meeting in conjunction with the APCO International Conference in Denver on August 13th.  At that meeting, a Board of Directors and Officers were elected. 


Del Smith stepped down as Chairman.  He will remain on the Board.  Del was recognized for his many years of leadership, support, and service.  Cindy Cast from Miami Dade County was elected as the new PTIG Chairman.  Cindy Cast serves as the Radio Systems Manager in the Information Technology Service Department, Radio Communication Services Division of Miami-Dade County, She is responsible for the management, maintenance, repair, and uninterrupted operation of the 800 MHz/700 MHz P25 trunked simulcast radio systems.  The 800 MHz Radio system has over 30,000 radio users.  Ms. Cast holds a Bachelor’s Degree in Management Information Systems (MIS) from Barry University and a Masters Certificate in Project Management from Florida International University (FIU).


With respect to the other PTIG Officers: Jim Holthaus from BK Technologies remains as Vice Chair, Jim is also deeply involved in the P25 standards process as TIA Private Radio Section and TIA TR8.25 chair.  Chris Lougee from 5x9 Communications remains as treasurer. Chris was formerly a VP at ICOM and the TIA PRS chairman before forming his new consulting group.  Andy Davis from Motorola Solutions remains as Secretary.  Andy is also a leader in the P25 Standards development process as the current TIA TR-8 Chairman.


Departing the PTIG Board were Jim Junkins, Roy McClellan, and Sanjay Patel.  Thanks and recognition were extended to them for all for their service.  New on the Board are Chris Maiers, SWIC from the State of Iowa, Karthik Rangarajan from EF Johnson, and Dominick Arcuri from DVA Consulting. 


Other P25 radio Users and practitioners returning to the PTIG Board include: Del Smith- Alaska ALMR, Christie Bielby-Texas DPS; Brent Finster-University of Hawaii, Scott Wright-State of Connecticut, Brad Stoddard-State of Michigan; Brandon Diemer-BLM NIFC, Eric Davies- DHS; Karl Larson-City of Portland; John Richards-State of Maine; George Crouch-State of South Carolina and Vice Chair Project 25 Steering Committee; Eric Linsley-Mobile County Alabama.  


PTIG Board returning Commercial Members include: Andy Davis-Motorola Solutions, Chris Lougee 5 x 9 Communications; Jim Holthaus BK Technologies, Cheryl Giggetts-AECOM; Neil Horden-Federal Engineering; Doug Chapman-Etherstack; Robin Grier-Catalyst, Todd Perdieu-Harris.


Stephen Nichols was appointed to continue as Executive Director for the non-profit organization.





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