[80]. When commands, signals, and orders are used. Commands only are employed in drill at attention. Otherwise either a command, signal, or order is employed, as best suits the occasion, or one may be used in conjunction with another. (31)
[81]. Instruction in use of signals; use of headdress, etc., in making signals. Signals should be freely used in instruction, in order that officers and men may readily know them. In making arm signals, the saber, rifle, or headdress may be held in the hand. (32)
[82]. Fixing of attention; a signal includes command of preparation and of execution. Officers and men fix their attention at the first word of command, the first note of the bugle or whistle, or the first motion of the signal. A signal includes both the preparatory command and the command of execution; the movement commences as soon as the signal is understood, unless otherwise prescribed. (33)
[83]. Repeating orders, commands and signals; officers, platoon leaders, guides and musicians equipped with whistles; whistles with different tones. Except in movements executed at attention, commanders or leaders of subdivisions repeat orders, commands, or signals whenever such repetition is deemed necessary to insure prompt and correct execution.
Officers, battalion noncommissioned staff officers, platoon leaders, guides, and musicians are equipped with whistles.
The Major and his staff will use a whistle of distinctive tone; the captain and company musicians a second and distinctive whistle; the platoon leaders and guides a third distinctive whistle. (34)
[84]. Limitation of prescribed signals; special prearranged signals. Prescribed signals are limited to such as are essential as a substitute for the voice under conditions which render the voice inadequate.
Before or during an engagement special signals may be agreed upon to facilitate the solution of such special difficulties as the particular situation is likely to develop, but it must be remembered that simplicity and certainty are indispensable qualities of a signal. (35)
Orders
[85]. Orders defined; when employed. In these regulations an order embraces instructions or directions given orally or in writing in terms suited to the particular occasion and not prescribed herein.