How long until phone privileges?

Well it happened today- my LO was transferred to the prison from the jail (happened while we were on the phone 😭😭). I know which prison he’s at because of inmate locater in Minnesota, but how long should I expect until he’s able to make a call? It’s been about 6 hours and I know he’ll call me as soon as they let him, but any idea when that would be?

Thank you all, I’m very new to this 😭❤️