Editing Project 25 (section)

{{Short description|Set of telecommunications standards}}
{{this|the telecommunications standard|the Heritage Foundation policy proposals|Project 2025}}
{{More citations needed|date=November 2019}}
[[File:P25 hand-held radios.jpg|right|thumb|300px|Several hand-held Project 25 radios used around the world]]'''Project 25''' ('''P25''' or '''APCO-25''') is a suite of [[Technical standard|standards]] for [[Interoperability|interoperable]] [[Land mobile radio system|Land Mobile Radio]] (LMR) systems designed primarily for [[Public security|public safety]] users. The standards allow [[Analog signal|analog]] conventional, [[Digital radio|digital]] conventional, digital [[Trunked radio system|trunked]], or mixed-mode systems. P25 was originally developed for public safety users in the [[United States]] but has gained acceptance for public safety, security, public service, and some [[Professional mobile radio|commercial applications]] worldwide.<ref>{{Cite web|title=What is P25 Technology?|url=http://www.project25.org/index.php/technology/what-is-p25-technology|url-status=live|archive-url=https://web.archive.org/web/20200429181123/http://www.project25.org/index.php/technology/what-is-p25-technology|archive-date=29 April 2020|access-date=17 November 2020|website=Project 25 Technology Interest Group|language=en-gb|quote=Project 25 (P25) is the standard for the design and manufacture of interoperable digital two-way wireless communications products. Developed in North America with state, local and federal representatives and Telecommunications Industry Association (TIA) governance, P25 has gained worldwide acceptance for public safety, security, public service, and commercial applications...The P25 standard was created by, and is intended for, public safety professionals.}}</ref> P25 radios are a direct replacement for analog [[Ultra high frequency|UHF]] (typically [[Frequency modulation|FM]]) radios, adding the ability to transfer data as well as voice for more natural implementations of [[encryption]] and [[text messaging]]. P25 radios are commonly implemented by [[Dispatch (logistics)|dispatch]] organizations, such as [[police]], [[fire]], [[ambulance]] and emergency rescue service, using vehicle-mounted radios combined with [[Repeater|repeaters]] and handheld [[walkie-talkie]] use.

Starting around 2012, products became available with the newer phase 2 [[modulation]] protocol, the older protocol known as P25 became P25 phase 1. P25 phase 2 products use the more advanced AMBE2+ vocoder, which allows audio to pass through a more compressed [[baud|bitstream]] and provides two [[Time-division multiple access|TDMA]] voice channels in the same RF bandwidth (12.5&nbsp;kHz), while phase 1 can provide only one voice channel. The two protocols are not compatible. However, P25 Phase 2 infrastructure can provide a "dynamic transcoder" feature that translates between Phase 1 and Phase 2 as needed. In addition to this, phase 2 radios are backwards compatible with phase 1 modulation and analog [[Frequency modulation|FM]] modulation, per the standard. The [[European Union]] has created the [[Terrestrial Trunked Radio]] (TETRA) and  [[Digital mobile radio]] (DMR) protocol standards, which fill a similar role to Project 25.