SDA Security, a San Diego-based security business that was founded in 1930, said it was acquired by Bay Alarm for an undisclosed price.

With the purchase, Bay Alarm will expand its presence in the San Diego and Inland Empire markets.

Shandon Harbour, president of SDA Security, said as the business researched how it could best provide cutting-edge services to customers, it became clear that joining Bay Alarm would be the best way to achieve that. “We know that Bay Alarm would be the right choice for future growth,” she said.

Founded in 1946 by Everett Westphal, Bay Alarm said it is the largest privately held alarm company in the nation. It maintains 14 branches in California.