Oral (that is, voice) communication is often difficult or impossible under combat conditions. At times, complete silence must be maintained. Under such conditions, signals are used to transmit commands or information. Three types of combat signals are used:

1. Whistle signals

2. Special signals

3. Arm and hand signals

Understanding combat signals is important for a fire team. Make sure you become thoroughly familiar with each signal described in this section. Bear in mind, too, that practice in the use of combat signals is essential if the signals are to be used effectively.

Whistle Signals

As a rule, only three whistle signals are used, since a large variety could cause confusion. The following three are commonly used whistle signals:

1. ATTENTION TO ORDERS is indicated by one short blast on the whistle. It is used to fix the attention of unit members on the unit leader who gives the signal and means that other signals, orders, or commands are to follow.

2. CEASE FIRING is indicated by one long blast on the whistle. This signal is verified immediately by an arm and hand signal or by some other means.

3. HOSTILE AIRCRAFT or MECHANIZED VEHICLE is indicated by three long blasts repeated several times.

Special Signals

Special signals cover all the special methods and devices used to transmit commands or information. Rifle shots or automatic rifle bursts maybe used when the entire command knows their meanings and the sound

Figure 11-28.-Combat arm and hand signals.

is distinct enough to be heard easily. A squad leader operating at night may find the use of raps on his helmet or rifle effective. Signals must be determined and practiced before they are used. Various pyrotechnic and smoke signals may be chosen as signals to attack, withdraw, mark front lines, or indicate targets. Certain special signals are standard for all branches of the armed forces to indicate the approach or presence of hostile aircraft or mechanized vehicles. They are as follows:

1. Three long blasts of a whistle, vehicular horn, siren, or Klaxon repeated several times.

2. Three equally spaced shots with rifle or pistol.

3. Three short bursts of fire from automatic small arms.

In daylight, an individual giving the signal should point toward the danger; at night, the alarm should be supplemented by voice warning to indicate the direction-for example, ENEMY TANKS AP-PROACHING BY THE NORTH ROAD or HOSTILE AIRCRAFT APPROACHING FROM THE WEST. Unit leaders should devise special signals whenever they appear to be useful in a particular situation. Before devising a special signal for the unit, the leaders should make certain that higher authority has not assigned some other meaning to the same signal.