The Enhanced Configuration System (ECS) is a privately developed addon for Armed Assault by the ECS team.
It was riginally written for Operation Flashpoint in 2005, to increase the Co-operative gameplay, game environment, effects, and AI reactions. The project was completely reworked for Armed Assault in February 2007. Since then, the project has grown and expanded to include many features far beyond it's original inception.
The mod was expressly intended for co-op use only and is not geared to PvP missions. It is however fully compatible in both single and multiplayers modes, including the campaign and Queen's Gambit.