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  Association of Public Safety Communications Officials -

  Project 25




Open Standard/Proprietary








Typical frequency band


Channel bandwidth

25/12.5 kHz

* The standard allows analog mode in radio terminal for backward compatibility with analog radio

What is APCO-25


APCO-25 (Association of Public Safety Communication Officials Project 25) is an open standard for digital radio developed in North America under state, local and federal representatives and Telecommunications Industry Association (TIA) governance. The standard was developed to foster the development and progress of the art of public safety communications.


In 1989, APCO formed a Working Group, called APCO Project 25, to work on development of a digitally trunked radio system specifications tailored to public safety needs. Project 25 was established to provide an industry-wide effort to set standards for uniform digital two way radio communications for public safety and emergency services.


APCO-25 brings together representatives from various associations and agencies to obtain as many contributions as possible to make the resulting specification a world standard for digital land public safety mobile radio. The objective is to find solutions that best serve the needs of the public safety marketplace. In addition, the committee has encouraged the participation of numerous international public safety organizations, making this a worldwide recommended standard-setting initiative. Worldwide interest has been generated due to the standards process being pursued by users working closely with the industry.


As APCO is an association representing users, assistance was sought from industry in developing the standard. The Telecommunication Industry Association (TIA) provided technical support and the mechanics of standard writing, which has made the resulting specification (ANSI/TIA 102) into a national industry standard. Published P25 standards suite is administered by the Telecommunications Industry Association (TIA Mobile and Personal Private Radio Standards Committee TR-8).




APCO-25, APCO-Project 25, APCO-P25 are all refer to the same standard name.


APCO P25 Capabilities and Features


From end user point of view, APCO-25 provides, among others:

  • Group call

  • Individual call

  • Telephone Interconnect Call

  • Wireless data

  • Integrated Voice and Data

  • Secured network with encryption

  • Talk Around mode

  • Backward compatibility with analog

  • Advanced radio features and capabilities such as Dynamic Grouping, emergency call, etc

Click here for more details on APCO-25 features.


Spectrum Utilization


APCO P25 utilizes Frequency Division Multiple Access (FDMA) techniques to achieve spectrum efficiency. At present, APCO can achieve up to 2 (two) voice channels in one 25 KHz radio channel.


Frequency Band


Frequency bands for APCO-25 products that are typically found in the market today:

  • 136 174 MHz (VHF)

  • 403 512 MHz (UHF)

  •  800 MHz Band

Backward Compatibility with Analog


APCO-25 standard allows backward compatibility with analog system. APCO-25 radio can directly interoperate with analog radios that are using the same frequency (note: direct interoperation here means direct communication among radios without using network infrastructure). With this capability, APCO-25 allows some smooth migration from analog system to digital. Users who already own analog system can migrate to digital by phases. Thus, users can decide to upgrade to digital system based on their needs, timing and resources.


Trunked and Conventional in One Network


APCO-25 supports combination of conventional and/or trunked system in one network. This gives user an advantage to have an option to deploy trunked system in high density area and conventional in less density area.


Network Architecture


Click here to learn typical APCO-25 architecture


Deployment of APCO-25


APCO25 Interoperable equipment or networks has been installed in more than 50 countries, mostly in Americas, Australia, Asia and some part of Africa.



More about this technology:



Manufacturers offering APCO-25:

(In alphabetical order)

The following list is not exhaustive:

  • Daniels Electronics

  • Datron World Communications

  • EF Johnson

  • Kenwood

  • King Communications

  • M/A-COM (a unit of Tyco Electronics)

  • Motorola

  • Thales Communications (formerly Racal)

  • RELM Wireless / BK Radio

  • TAIT

  • Westel Wireless (formerly ADI)

  • Wulfsberg Electronics

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