Editing Project 25 (section)

=== P25 open interfaces ===
P25's Suite of Standards specify eight open interfaces between the various components of a land mobile radio system. These interfaces are:

* Common Air Interface (CAI) – standard specifies the type and content of signals transmitted by compliant radios. One radio using CAI should be able to communicate with any other CAI radio, regardless of manufacturer
* Subscriber Data Peripheral Interface – standard specifies the port through which mobiles and portables can connect to laptops or data networks
* Fixed Station Interface – standard specifies a set of mandatory messages supporting digital voice, data, encryption and telephone interconnect necessary for communication between a Fixed Station and P25 RF Subsystem
* Console Subsystem Interface – standard specifies the basic messaging to interface a console subsystem to a P25 RF Subsystem
* Network Management Interface – standard specifies a single network management scheme which will allow all network elements of the RF subsystem to be managed
* Data Network Interface – standard specifies the RF Subsystem's connections to computers, data networks, or external data sources
* Telephone Interconnect Interface – standard specifies the interface to Public Switched Telephone Network (PSTN) supporting both analog and ISDN telephone interfaces.
* Inter RF Subsystem Interface ([[P25 ISSI|ISSI]]) – standard specifies the interface between RF subsystems which will allow them to be connected into wide area networks
* Key Fill Interface (KFI) - standard messaging protocol for bidirectional update of encryption keys via transfer of unencrypted and encrypted key variables from a Key Fill Device (KFD) to the equipment containing the encryption service
* Inter-KMF-Interface (IKI) - interface for encrypted interoperability between radios managed by different Key Management Facilities (KMF)
* KFD-KMF Interface - interface between KFD and KMF for radios managed by different KMF (under development)<ref>{{Cite web |date=March 2025 |title=Statement of Project 25 (P25) User Needs |url=https://www.cisa.gov/sites/default/files/2025-03/25_0319_s-n_statement_of_p25_user_needs_508C.pdf |url-status=live |archive-url=https://web.archive.org/web/20250505141551/https://www.cisa.gov/sites/default/files/2025-03/25_0319_s-n_statement_of_p25_user_needs_508C.pdf |archive-date=5 May 2025 |archive-format=PDF |access-date=10 May 2025 |website=[[Cybersecurity and Infrastructure Security Agency]] |format=PDF}}</ref>