radio!, excl. — Green’s Dictionary of Slang

radio! excl.

[the two-way radios carried by guards; the term initially used to warn of an approaching radio or guard, widened into a general imper. implying ‘Shut up and listen to your radio!’]

(US prison) be quiet! stop that!

[1931–4		D. Clemmer Prison Community (1940) 335/1: radio, n. A convict that talks loudly and frequently].
1967		M. Braly On the Yard (2002) 55: A door crashed [...] and a sighing murmer ran through the block as if the men had collectively groaned and turned in their sleep. ‘Radio,’ some man called irritably.
1977		L. Heinemann Close Quarters (1987) 29: Listen up, radio, y’ slam that do’ one mo’ time an’ ya goes hungry.
1981		Maledicta V:1+2 (Summer + Winter) 264: An inmate demanding quiet yells Radio that! or Radio that shit!
2000		Other Side of the Wall: Prisoner’s Dict. July 🌐 Radio: An old term asking for quiet.