The 5-2 is the standard for many coaches at the high school level and is used somewhat extensively at the collegiate level. Consisting of a nose guard, 2 defensive tackles, and 2 defensive ends, it is intended mainly as a run defense. However, it can be effective against the pass as well with five pass rushers and two or three linebackers.
Usually, the down linemen's first responsibilities are running lane specific, each man responsible for a certain gap or lane. The default command for linemen is to read and react to the play, with the defensive end's primary concern being containment. Occasionally, a defensive end may be called on to pass defend an area such as the flat. By design, the line backer's first responsibility is to defend the run, then the pass. But this may be modified for varying purposes. A coach wants his leading tacklers to be down linemen or line backers. If a defensive back or safety is leading the team in tackles, it is a clear indication that the opposing offenses are getting throughout the first line of defense.
The remaining four positions are the two corner backs and the two safeties. An option is to allow one of the safeties to be a "free safety" meaning that this player seldom has specific duties, and is left to read and react to each play. If in zone pass coverage, the free safety or safety to the TE side has "up" responsibility, while the strong safety has deep third duty. Each corner has deep third duty as well. LBs are 4 to 5 yards off the ball, CBs 3 to 6 yards deep, safeties 10 to 12 yards. Down linemen keep the ball in the corner of the eye, and move on the snap--not the QB's vocalizations or other personnel movement.