Siren systems are used worldwide to notify communities of incoming threats, including tornadoes, wildfires, air raids and nuclear events.
Although these systems have been a vital asset for alerting citizens of danger for over 50 years, the vast majority have a fatal flaw: they rely on analog designs with unencrypted code signals that are susceptible to being hacked.
In early April 2017, Dallas metropolitan residents were shaken from bed from the sound of 156 tornado sirens blaring purportedly due to such a radio-frequency hack. Erroneous alerts like this can easily flood 911 lines from concerned citizens; continued attacks can also lead to residents ignoring important alerts if they think it is another false notification.
Jim Morris, radio system manager in Oklahoma City, had been keenly aware of Dallas' 2017 event and was concerned about his city's system vulnerabilities. Oklahoma City is located in "Tornado Alley" of the United States and relies heavily on its system of 182 separate sirens to alert the community of impending disaster.
A Stretch Assignment
While L3Harris is not in the mass-notification business, the company’s commitment to its customer led to an innovative solution that leveraged cross-industry collaboration to meet Oklahoma City’s need.
“We had an embedded customer who reached out to us with a novel problem, and we responded 100% as a team,” Dan Deveson, L3Harris distributor and president of Shared Solutions Technology, LLC, said. “We understood the risks, moved forward and mitigated those risks by working as a team. We delivered a system that works much better than the old one, responding to a real customer need and took on the challenges that no one else would.”
Oklahoma City is an existing L3Harris Project 25 system customer. Based on the vital nature of the system, it cannot go down at any time. A plug-and-play solution for secure siren notifications within the existing network was a natural and seamless fit, according to Deveson.
“Our P25 radio system has multiple layers of security, redundancy and reliability, and our maintenance resources are focused on every single radio call,” Morris said. “To integrate siren operations away from ancient analog systems was a reliability dream we worked long and hard to achieve.”
Available off-the-shelf products did not meet Oklahoma City’s requirements, so L3Harris led a team of customers and vendors to design and deploy a P25 solution integrated with existing siren controller designs and leveraging the company’s Medium-Rate Advanced Encryption Standard Unit (AES).
A Secure Siren Solution
Now, instead of a hackable analog system, Oklahoma City’s sirens can leverage the L3Harris P25 simulcast system already in place and benefit from the 256-bit federal standard encryption within the AES.
L3Harris teamed with a market leader in emergency mass notification and products to complete a unique board change. This included integrating L3Harris radios into the siren control boards to establish a highly redundant, secure system that conducts siren call codes on the same digital channels emergency personnel use for voice communications, according to James Potter, L3Harris Product Management director.
“We based our design on industry and open-systems standards, worked with a trusted partner and adapted a customer product to deliver an unstoppable solution that is working phenomenally,” Potter said, adding that the solution can work on any P25-capable system. “We leveraged all the redundancy of Oklahoma City’s existing Land Mobile Radio network, added AES encryption, and made the city agency’s most-critical infrastructure easier to operate.”
The AES-enabled solution is “flea size” compared to alternatives – comprising solely radios and cables – and showcases the expanded potential and application of Project 25 networks, Deveson added.
The innovative one-system approach should reduce logistics and maintenance costs for Oklahoma City’s P25 and siren systems as well, according to Potter.
