The present invention provides a relatively simple etalon testing system and process for measuring cavity error of etalons to high precision. The tensioner pulls or pushes the seat belt so that the few inches of slack that usually exist are eliminated by the tensioner. Legs are coupled to and extend from the shaft to support the shaft in an upright position on a supporting surface. Having identified the behavior preserving causality constraints, the corresponding lock and unlock statements in the concurrent program are identified which enforce the identified causality constraints. The method comprises the steps for:calculating a salience map in relation to the video part of said document,determining at least one audio descriptor representing said document,weighting the video salience map as a function of the variation of said audio descriptor. During this second period of time, the wireless device is operated in a standby mode such that RF transmissions are disabled.