Off the hook means - freed from danger or blame or obligation;

"I let him off the hook with a severe reprimand"

The duration of Guy Off the Hook is 1800.0 seconds.

Guy Off the Hook was created on 2008-09-14.

It's called an off hook tone. Or you can call it a receiver off hook tone or r.o.h. tone or a permanent signal.

It is fishing slang. If you are on the hook you are caught, trapped, obligated but if you get out of something, a commitment, or obligation you have been let off the hook.