Do you copy?

What does "Do you copy?" come from, what does it mean?

It a CB term that truck drivers use. It means, "Do you hear me?" or, "Did you get that?". Along those lines.

Here is a definition from Merriam-Webster on line for CB (citizens band):

Main Entry: citizens band
Function: noun
Date: 1948

a range of radio-wave frequencies that in the U.S. is allocated for private radio communications