American Alarm, a home and business security system company headquartered out of Arlington, Mass., has bought 5 contiguous condos located at 70 Zachery Rd. from Prom Real Estate out of Williston, VT. American Alarm is relocating their Windham, NH office to Manchester. The purchase price was $518,000. Deanna Caron from Stebbins Commercial Properties, Inc. represented the buyer and NAI Norwood represented the seller.