{{refimprove, date=November 2010 Bridging Systems Interface is a standard protocol for communicating with physical interfaces which attach analog or digital voice radios to digital data networks—known as '

Radio over IP Radio over Internet Protocol, or RoIP, is similar to Voice over IP (VoIP), but augments two-way radio communications rather than telephone calls. From the system point of view, it is essentially VoIP with PTT (Push To Talk). To the user it can be i ...

'--to make easier the use of remote radios by local users, and the sharing of radios by multiple users, in the service of improving

emergency An emergency is an urgent, unexpected, and usually dangerous situation that poses an immediate risk to health, life, property, or environment and requires immediate action. Most emergencies require urgent intervention to prevent a worsening ...

communications Communication (from la, communicare, meaning "to share" or "to be in relation with") is usually defined as the transmission of information. The term may also refer to the message communicated through such transmissions or the field of inqui ...

interoperability Interoperability is a characteristic of a product or system to work with other products or systems. While the term was initially defined for information technology or systems engineering services to allow for information exchange, a broader def ...

. The standard is promulgated by the SAFECOM program in the US

Department of Homeland Security The United States Department of Homeland Security (DHS) is the U.S. federal executive department responsible for public security, roughly comparable to the interior or home ministries of other countries. Its stated missions involve anti-te ...

's Office for Interoperability and Compatibility, specifically, the VoIP Working Grou

Technical Details

The working group has broken down the problem of moving public safety communications audio over data (usually TCP/IP) networks into 5 specific interface points: * Radio System Interface – an interface that enables VoIP communication to radio system infrastructure * Dispatch Interface – an interface to a dispatch console * End Unit (Software Device) Interface – an interface that allows a network-connected computing device to connect into a radio system using a software implementation * Radio Site Interface – an interface to a base station or similar device * Bridging Systems Enhanced Interface – additional functions of the BSI Core Profile, an interface between bridging or gateway devices To quote the working group's pseudo- Request for Comments, RFC standards proposa

:A bridging system is a device that enables voice communication among disparate radio frequencies, systems, or technologies. The disparate devices connected via a bridging device may include

land mobile Mobile radio or mobiles refer to wireless communications systems and devices which are based on radio frequencies(using commonly UHF or VHF frequencies), and where the path of communications is movable on either end. There are a variety of views ...

radios, analog phones, mobile phones, IP telephones, and personal computers; however, this is not an exhaustive list of connective devices. The interface through which bridging systems communicate with each other is the Bridging Systems Interface (BSI). This interface is based on SIP, the

Session Initiation Protocol The Session Initiation Protocol (SIP) is a signaling protocol used for initiating, maintaining, and terminating communication sessions that include voice, video and messaging applications. SIP is used in Internet telephony, in private IP telep ...

, and the document provides standardized mappings between that protocol and the actual functions that are provided by individual radio hardware, whatever those might be. Internet protocols Public safety communications Radio communications Interoperable communications