In the 1980’s cars were first equipped for remote diagnosis when the “check engine” light came on. At the dealer & dialed up to the factory. Then early laptops could plug into the car’s diagnosis socket & do the same.
I’ve got a 1977 Mercedes parked in a barn. May have to look at getting it running again. No black box no nuthin’.
73 Duster waiting in my garage. I call it the Red Barchetta.