You've seen it a thousand times in the movies: A person gets arrested, and then he or she has to decide whom to call
The police, after all, only allow one phone call. Does the alleged criminal call a lawyer, a friend, or a family member? He or she finally decides, dials the number, and no one picks up! The police say that it's too bad, you don't get another call, and the unfortunate person is stuck in jail with no support.
This is so commonly cited that many people think it's a law. Fortunately, this is not the case.
Many Factors
The reality is that there are many factors in play here, and it's not as simple as a one call law. You could get one, you could get a dozen, or you may not get one at all.
State Laws
How many calls you get does differ according to state laws, but even these aren't always a hard number. For instance, in Nevada, the law simply says you get a "reasonable number of completed telephone calls." They're not going to let you call everyone in your contact list, but the police aren't going to deny you your rights or unreasonably keep you from making calls, either.
Your Rights
As this shows, it's critical to actually know your rights if you're arrested. Never assume anything or get your information from unofficial sources - like the movies.