Senior Airman Cassandra Dyer, a computer and communications operator, provides telephone operator assistance to participants of Exercise Roving Sands '97 on April 21,1997. More than 20,000 service members from all branches of the armed forces of the U.S., Canada, Germany, and the Netherlands are participating in Exercise Roving Sands '97. The exercise is designed to refine their skills in operations using an integrated air defense network of ground, missile and radar early warning systems combined with tactical fighter and bomber aircraft operating in a simulated high-threat environment. Dyer, who is attached to the 729th Air Control Squadron, is one of the many U. S. and international military members providing command and control communications for Roving Sands '97.