P25, or Project 25, is a suite of standards developed to provide digital voice and data communication systems suited to public safety and first responders. Project 25 was initiated by APCO

The TIA, formulates and maintains the TIA-102 series of standards for APCO P25, on behalf of APCO International.

The Project 25 standards enable interoperability among multiple manufacturers of P25 products. This results in a greater range of products, both mobile and portable radios used

P25 phase 1 uses FDMA, P25 phase 2 uses TDMA