Voice over Internet Protocol (VoIP) technology is increasingly important in EMS communications, but it's developed without a single standard embraced by all manufacturers. Accordingly, there's no guarantee Maker A's equipment will be able to interface with Maker B's—and that's a problem you don't want in times of trouble.

     The Public Safety VoIP Working Group is hoping to help remedy it. Working in conjunction with the Department of Homeland Security's Science and Technology Directorate, the group—which includes representatives of the emergency services, communications vendors and the National Institute of Standards and Technology's Office of Law Enforcement Standards—has developed common specifications for VoIP-based bridge devices to use to interconnect. Half a dozen top vendors successfully linked using the resulting standard—known as the bridging systems interface, or BSI—during an April demonstration at NIST's headquarters in Boulder, CO.

     "The issue is, how does the industry facilitate broader adoption of technologies that enable communications interoperability?" says James Mustarde, director of marketing for software producer Twisted Pair Solutions (www.twistpair.com), which joined Motorola, Cisco, Clarity Communications, Sytech and Valcom for the demonstration. "This is a way of facilitating interoperability by having the various solution providers build to a certain standard, so that each of their individual 'islands' of interoperability can be trunked together."

     "Islands" are essentially the problem here. You may have VoIP-based interoperability within your metro area or region. But can you connect to other, similarly discrete network units elsewhere across your state? A common standard for the interface of bridging systems would ensure that you could.

     The BSI is based on Session Initiation Protocol (SIP) technology. SIP is a popular signaling protocol used for multimedia communications like voice and video over the Internet. Its wide use in other applications should make it easy to build to in the VoIP realm. And with the standard's broad adoption, manufacturers will have every incentive to do so.

     "If I go out tomorrow to buy a system, I'll want to make sure it interoperates with my existing system, and the standard can ensure that," Mustarde notes. "Of course the rate at which manufacturers will start building to a standard varies, but I think we'll see that interoperability is considered a very urgent requirement."

     Officials with DHS' Office for Interoperability and Compatibility (OIC) will utilize the BSI as part of their Radio over Wireless Broadband (ROW-B) project, which aims to integrate new broadband technologies with existing public safety radio systems. For more, see www.safecomprogram.gov.