Suspend firing. A long blast of the whistle. All other whistle signals are prohibited. (42)
Arm Signals
[92]. The following arm signals are prescribed. In making signals either arm may be used. Officers who receive signals on the firing line "repeat back" at once to prevent misunderstanding.
Forward
Forward, MARCH. Carry the hand to the shoulder; straighten and hold the arm horizontally, thrusting it in the direction of march.
This signal is also used to execute quick time from double time.
Halt—arm held stationary
Double Time— arm moved up and down several times