Alarm Detection Systems Inc. (ADS), Aurora, Ill., has bought the assets of Comstar Inc., which services more than 2,000 accounts. This represents one of the largest purchases made by ADS, which ranks as No. 21 on the 2005 SDM 100.

A sister company to Comstar, Star Security, primarily a union installation contractor, will remain in business. Ron Davis, managing partner of Davis Marketing Group, represented the seller, Comstar, and handled the negotiations with ADS.

"Start to finish, this deal was done in less than six weeks," Davis noted. "It's a testimonial to both Terry Olah, chief financial officer of ADS, and Jim Greco of Comstar as to the quality of the work they did, as well as their dedication to the process."