US radio callsigns

I just finished Antal's "Infantry Combat: The Rifle Platoon." Very cool, but
the callsigns for communication within the platoon weren't
explained (that I noticed-- it didn't detract from the book, FYI).
One-six, one-three, one-four, etc... including Bravo one-six (I
believe Bravo to be the platoon designation...it's been a few days)

> One-six, one-three, one-four, etc... including Bravo one-six (I

I can't speak for "old school"," but typically Bravo would be a company
designation. At higher levels, numbers indicate battalion and regiment.
However at lower levels, they usually indicate platoon and squad.