Re: Meaning and origin of term I've heard in a few movies

I'm certain someone will do better, but in all the movies I've seen,
going
back to mouldy oldies, it's related to communications. Usually: I read
you
five by five.

Somehow I got the impression it was the strength of the signal by the
clarity of what was coming through, but that may have just been my
imagination.

The_Beast