alertmediaAlertMedia, a platform for interactive mass notification, announced Tuesday it has raised $4 million more in a Series A-1 funding round.

Silverton Partners led the round which included ATX Seed Ventures and other current investors.

The Austin-based startup announced last June that it had raised $4.16 million in Series A funding. The latest round is to support AlertMedia’s expansion in the emergency communications market. Its mass communications platform now serves tens of thousands of users in more than 80 countries, according to a news release.

“Silverton is very excited to continue our investment in the AlertMedia team,” Morgan Flager, partner at Silverton Partners and AlertMedia board member, said in a news release. “The company has developed a world-class product, which is in high demand across the dozens of industries AlertMedia already serves.”

AlertMedia serves customers in manufacturing, telecom, healthcare, business services, transportation, energy, government, financial services, real estate and education. They use the company’s platform to “protect their workers, automate operations and mitigate loss.” Its customers include AT&T, Volkswagen, DHL, Pitney Bowes, Kellogg’s, Deluxe Corp., Tokyo Electron and the state of Texas.

AlertMedia recently launched SafeSignal, a patented worker safety solution.

“Our goal is to continue developing amazing products, and deliver those products to enterprise customers who want to keep their people safe, informed and connected,” Brian Cruver, founder and CEO of AlertMedia, said in a news release.