Prisoners can make phone calls in the detention center, which is not allowed by law, because outside contact is not allowed before the criminal suspect has closed the case, and the phone calls can only be made by the police, and all people related to the law or the case are not allowed to inform the criminal suspect.
Being put in a detention center can only prove that you are suspected of committing a crime at this stage. No one is innocent until convicted by the court. If the investigation organ has insufficient evidence or the court decides not guilty after being put into the detention center, the detainee can be released.