Showcasing Mass. and the military

Milcom 2009, the largest international conference on military communications, is in Boston through tomorrow, attracting more than 250 companies, and about 3,750 participants, to the World Trade Center and Seaport Hotel on the South Boston waterfront. The four-day event features more than 450 technical presentations, dozens of panel discussions and tutorials, and hundreds of exhibits that feature wearable computers, onboard technologies for military vehicles, and battle-ready portable communications systems.

The annual conference, which was started as a small gathering in a Route 128 hotel in 1981, now rotates among a cluster of cities. But this year’s edition, hosted by General Dynamics C4 Systems, which has a facility in Taunton, and the Mitre Corp. in Bedford, showcases not only the size of the state’s military industry, but its strength in communication and networking.

The most recent study of the Massachusetts defense sector by the University of Massachusetts’ Donahue Institute in November 2007 estimated defense spending by federal agencies totaled $9.2 billion and generated an additional $5.5 billion in indirect spending. In 2005, the year the study analyzed, defense-related spending accounted for 4.6 percent of the state’s gross domestic product.

At this year’s conference, at least 27 companies on the exhibit floor are either based in Massachusetts or have a significant presence here.

“Milcom represents the real strength of the Massachusetts military sector,’’ said Donald Quenneville, the executive director of the Defense Technology Initiative, an industry group that promotes defense technology in New England. “We don’t have a large active duty presence, like a Langley Air Force Base in Virginia; we don’t build tanks or aircraft. What we do is research and development, and technological innovation.’’

Quenneville cited the Electronic Systems Center, located at Hanscom Air Force base in Bedford, and the US Army Soldier Systems Center in Natick as examples of the kind of military operations that are typical of the Massachusetts military sector.

On the show floor yesterday, General Dynamics displayed a “Land Warrior’’ system developed by its C4 Systems division. The system, which includes a camouflaged vest stuffed with computer and networking technology, connects “the soldier at the pointy end of the spear with higher operations and all the way back to strategic,’’ said company chief executive Chris Marzilli.

The market for General Dynamics military technology has expanded in recent years, Marzilli said, because it is being adopted “closer to home’’ by agencies concerned with homeland and border security. Buyers from domestic security agencies and the four branches of the military make up the target audience for most exhibitors, Marzilli added.

At Mitre’s booth, a scale model of an unmanned aerial “Predator’’ vehicle was on display next to a collection of small, lightweight, battery-operated beacons developed by the Bedford company.

Mitre’s technology “enables a new level of awareness among smaller aircraft,’’ said Brian McHugh, a member of the company’s technical staff.

Raytheon Co., headquartered in Waltham, has a large, two-story display at the show. On the top floor, Lucas Bragg demonstrated the “MAINGATE’’ networking system, which can quickly establish Internet-like connectivity on the battlefield.

“If you can leverage technology, you can multiply the effectiveness of every soldier on the ground,’’ Bragg said.

BBN Technologies, the pioneering Cambridge research and development firm that was one of the developers of ARPANET, the predecessor to the Internet, is also at the show.

BBN, which was bought by Raytheon in September, demonstrated its “K-Node Testbed’’ battlefield network emulator, which simulates connectivity among soldiers, satellites, and unmanned aerial vehicles. The networking capabilities of the system were displayed on large flat screen monitors, overlaid on a Google Earth image of a war zone.

“We’ve been around for 61 years, that’s a lot of expertise,’’ said BBN spokesman Mark Gauthier. “It makes sense to apply that to tactical, battlefield situations.’’

The theme of the Milcom conference is “the challenge of convergence,’’ a recognition of the proliferation of connected technologies and devices in today’s war zones, said Quenneville.

But Quenneville added that the theme also works as an excuse to showcase the state’s technical strength and networking expertise.

“As we do more and more joint operations, interoperability becomes more important,’’ Quenneville said. “Ultimately, we all want to be able to talk to one another on the battlefield. And, fortunately, that takes the kind of networking expertise that we have here in Massachusetts.’’

D.C. Denison can be reached at denison@globe.com.