The only way you are going to know is to listen to the recording when you get a call. It tells you that you are receiving a call from the correctional facility. The person calling you records their name in their own voice. You have a choice whether or not to accept the call from that person.
I am NOT a shill---just a good samaritan trying to help. That's what this website is for.
And what you just said had nothing to do with the original comment. Let me put it in a way you can understand: posts on the net are typed by someone, they don't appear as if by magic on other sites because you posted here. And did you ever hear of caller ID spoofing? The number may be legit, but scammers can SPOOF the number to make themselves look legit when the call is nothing of the sort. Do a little research before you come back and reply
The op is unclear and unhelpful. Why posting? Do they know someone in the Big House? Did someone using "Franklin Correctional" try to scam them? I don't quite buy the story of "just a good samaritan trying to help", since there is not enough info provided by the op to be any darn help at all. And I hate to generalize, but a when I hear a fractured, partial short story, I am thinking Shill.
In other news: In some locations the call will cost money, and sometimes a LOT of money. There is incentive there for a shill. If that is the case here, I do not know. You are right about one thing, if you have been reached by mistake, don't accept a call.
I just did a sloppy search of "Phone calls from prison scams" and just scanning the links to everyone from AARP to Verizon, tells me that calls out of the blue from an inmate or prison are ifffy at best.