General Dynamics expects the move to increase its earnings beginning in 2012.
General Dynamics C4 Systems will manage the acquired company, which employs around 70 workers.
Massachusetts-based Fortress provides ruggedized and other networking products for battlefield logistics, convoy, command post and soldier applications.
“The acquisition of Fortress accelerates our ability to deliver a wider array of secure, Wi-Fi-based tactical wireless communication systems for military and government users worldwide, ” said Chris Marzilli, president of General Dynamics C4 Systems. “These competitively priced products, based on commercial offerings, deliver unprecedented efficiencies in size, weight and power for users from the core to the very edge of the network.”