if someone has an inmate number does that mean they are actively in prison? I found info that a friend is in jail. I tried to send a letter on here. can he write me back? or call if I sent a number?

Yes to all of the above. Inmate ID means they have been in jail, whether they have been released might not be available. You may write him from here and he can respond through if he chooses to. If he has your phone number, he can call you as long as he has money on his books or you accept a collect call. Collect calls are about $15 each. If you are intending to speak often, we would recommend you look into our Discount Telephone Service, it'll save you both a lot of money.