Maybe this is a dumb question, but how did the call-ins work then? There was always a message if it was a rerun (don't try really calling, etc.) but even their

Maybe this is a dumb question, but how did the call-ins work then? There was always a message if it was a rerun (don't try really calling, etc.) but even their last shows had what appeared to be live call-ins and a call-in number and I remember them having to advise people to turn the radio off while they're on the phone.