Once the climber falls, he is out of position and fully loading the anchors. The anchor is very important to fixed lines. Since there is no belayer in position to absorb any of the load in the event of the fall, the top anchor must be fail-safe. There may be other anchors in the line holding the line in the correct place or anchoring the bottom. These, though important, are not nearly so crucial as the top anchor, from which the entire system hangs.
Communication is the final element necessary to consider.
Since the climber belays himself, you might think that there is no need for signals, but the climber needs to know when it is safe to get on the line. Generally, because a fall by one climber would pull others off their feet, climbers travel on fixed lines one at a time. Because the lines are sometimes used nearby or in conjunction with 5th Class belays, the signals should sound very different from others. The 5th Class system offers the most security. It was described at the beginning of this chapter, so I won't reiterate it here.