Hey PERCOM ... and a few others ....
Guys, why don't you do two things before you post asking questions that have already been asked and answered many times before
a - have a read of you study resource and b - check out the technotes ............
http://www.techexams.net/technotes.php
If you can't find your answer or are confused, THEN ask away and each and every member will be happy to assist
