a 10-4 - A 10-4 is like a police officer saying, "I heard you,&#3

A 10-4 is like a police officer saying, "I heard you," when they are chasing a criminal or trying to catch someone.

The cop said, "10-4, I heard you over the siren!"

He said, "10-4, I heard you from my car!"

She yelled, "10-4, I heard you from the back of the squad car!"