Can a principal keep you from calling your parents?

So i got a referral and detention in my school for standing up for myself and my friends during lunch. I asked the principle if i could calk my mom. He said no in a mean tone. Can they keep me from doing that?

It depends on the situation about letting some one call the Mom or dad.
If you don't mind me asking, what school are we talking about. Maybe I can
help you better. What I would have done was wait until I got home and
sit mom down and let her know what the problem was.
I would at that time know just where I stand.

Let me try this another way. This might help.

"School officials do not possess absolute authority over their Students.
 Students in school as well as out of school are "persons"  under our
 Constitution.  They are possessed of fundamental rights which the
 State themselves must respect, just as they themselves must respect their
 obligations to the State.  In our system, students may not be regarded as
 closed-circuit recipients of only that which the State chooses to communicate.
 They may not be confined to the expression of those sentiments that are
 officially approved.  In the absence of a specific showing of constitutionally valid
 reasons to regulate their speech, student are entitled to freedom of expression
 of their views".

 These are the words of Mr. Justice FORTAS.
I really hope this helps you. It really depends on what is said and how it is said.