Not sure what you mean. When a call was recorded, the caller was in fact talking in real time to Tom and Ray. the caller didn’t have to listen to the show (on the radio) to hear what Ray and Tom said, they were talking w/Ray and Tom on the phone. The callers were screened by the producers to insure the calls would be interesting and of general interest, but Tom and Ray were not privileged to that info before taking the call. They were just told to pick up the phone & talk to whoever was on the line. The main difference with a live call-in show was that Car Talk was taped on Thursday, then broadcast on the following weekend by the NPR stations, at whatever time each station chose.