Stations 600 (Greensboro), 700 (Goldsboro) , 400 (Ridgely), 300 (Denton) were dispatched to Commerical Box 6-1 for smoke in a building.  E604 arrived with nothing apparent 619 (F. Davis) assumed command.  E703 responding with a crew of 6 under direction from 716 (B. Cahall).  E702 responded with a crew of 3 with 715 (J.T. Bartz).  T706 responded with a crew of 3.  E604 took position on side A. and handled interior investigation.  E703 took position of Side B and ladder the building to check the roof.  L310 set up on A,B corner.  E702 handled the supply and hydrant.  After investigation it was deemed a faulty AC unit.  Provided positive pressure to clear the smoke.  All units cleaned up and returned to service after working for about a hr.  Other units on location E603, E401, T406, T706, C4