To help Project 25 (P25) users navigate the continuing evolution of P25 systems and the complex world of P25 Standards, the P25 Steering Committee, with support from CISA, developed the Statement of Project 25 User Needs (SPUN) as a framework for users to better understand P25 technologies and define their communications needs.

P25 land mobile radio (LMR) systems have long provided critical tactical and emergency communications capabilities to public safety agencies nationwide. The P25 Standards that define the technical foundation on which these interoperable systems rely are “built for public safety by public safety” and their development relies on collaboration between user and manufacturer communities. However, most LMR users lack both access to the P25 Standards and the time to read through volumes of technical documentation to fully grasp all the features and capabilities that P25 systems can provide or to engage in the standards development process.

To bridge this gap, the SPUN provides high-level explanations of P25 system architecture, features, and functions as defined in the Telecommunications Industry Association 102 Suite of Standards (P25 Standards) and recognized by P25 users and system administrators.  Building upon the original P25 Statement of Requirements document that guided initial P25 Standards development, the SPUN is divided into two sections to help readers quickly find the information they need: 

  • P25 Overview (Main Document)
    • P25 general features, functions, and services
    • P25 Interfaces
    • P25 system types and modes
    • P25 system components
  • P25 User Needs List (Appendices)
    • Specific user needs across different system modes (i.e.,trunking and conventional)
    • Features, functions, and services
    • User needs for different P25 interfaces

How does the SPUN benefit LMR users?

Since its inception, P25 has aimed at making interoperable radio communications as reliable, flexible and easy to use as possible, and the only way standards developers can know if they’re achieving that goal is through feedback from practitioners in the field. Until the SPUN, however, practitioners have had no easy way to understand the scope, capabilities and features of P25. The SPUN translates the more than 70 P25 Standards into relatable content to help public safety understand all the capabilities available to them through the standards. The SPUN also provides a reliable way for readers to know if the standards can address their unmet needs and how to frame their input to the P25 Steering Committee. The SPUN gives users practical guidance for identifying and prioritizing their needs and communicating them to the committee or manufacturers. The P25 Steering Committee and CISA encourage LMR users to read the SPUN and send any and all feedback, suggestions, and recommendations for P25 improvements to the P25 Steering Committee: Project25SC@cisa.dhs.go.

To learn more about P25, visit