Answer:

signals

Answer	Crossword Clue
SIGNALS	Warns about an impending turn
SIGNALS	Semaphore user's output
SIGNALS	Prepares to turn

SIGNALS	Indicators
SIGNALS	Turn indicators, e.g.
SIGNALS	Beckons
SIGNALS	Omens
SIGNALS	From catcher to pitcher.
SIGNALS	Weather flags.
SIGNALS	Quarterback's concern.
SIGNALS	Quarterback's repertoire

SIGNALS	High-low plays at bridge
SIGNALS	High-low ploys in bridge
SIGNALS	Quarterbacks' calls
SIGNALS	Red flags, e.g.
SIGNALS	Heralds
SIGNALS	Bridge stratagems
SIGNALS	They may get mixed in communication