Battle Stations 21 is the culminating event of the Navy Basic Training. In a series of scenarios lasting through the night, Recruits are tested on the teamwork and basic skills they will need when they report to their first ship. ETI developed the AVLS to function as a semi-automated system centered on a Scenario-media Control Unit (SCU), a scripted time-based controller operating under the supervision of other systems. The AVLS operates in modes as initiated by a network on hand-held controllers connected to an Overall Supervisory System (OSS). The audio system is made up of multiple digital audio playback modules configured to distribute and layer complex sounds into various areas of the Trainer while being synchronized with other events. The video system contributes to the immersive elements and scenario set ups of the training objectives using both standard format NTSC and HD format video image segments displayed on both projected and plasma displays. A Lighting Control Unit (LCU) controls virtually all the lighting in the Trainer. Battle Stations training has proven value. Members of the crew of the USS Cole, which was attacked by terrorists in Aden, Yemen in 2000, relate that the newest Sailors on board were well prepared with the skills and knowledge they were taught and tested on Battle Stations.