Legitimate call from a Correctional Facility in Colorado (my brother is in jail) and it will ask for a credit card to connect the call and/or set up an account.
Years ago, a family member who was living with me at the time was conned by a convicted felon who had been reincarcerated for VOP. I came home from work one afternoon and opened the mail to discover $30 had been tacked onto my phone bill to pay for incoming calls from a correctional facility. Turns out this individual had been calling and calling, begging for a bail bond.. I HIT the ceiling.. Not only did I put a stop to the calls (and the relationship), but also collected $30 to cover the calls. End of story.