thss alarm tells you that average time of busy RF timeslot is below treshold, last value in alarm shows the average time, so 4 sec. in your example, so this 7743 alarm is just a notice for you that probably something wrong with this cell because call duration is too short, may be they are dropped because of interference or transmission problem, in many times alarms 7745 occures together with 7743…
Alex
http://www.dx200.biz