It all depends on the age of the athlete and if it is DI, DII, DII. This should help:
http://www.ncaa.org/sites/default/files/Overview+Chart.pdf
So, am I reading this correctly that coaches can't call or initiate contact until the summer before the prospect's junior year of high school? How about acknowledging emails or letters? If you can't recruit prior to junior year, how are some sophomores already committed to major schools?