Spartan signals

Over their years of training and decades of combat, the SPARTAN-IIs and SPARTAN-IIIs have developed intricate shorthand communications systems for use among themselves. Many of these ideas are known and understood by the Spartans only, even as well-guarded secrets. These also sometimes make normal conversations with the Spartans impossible, as they can do a great deal inside their MJOLNIR armor that is indistinguishable from the outside. These signals include slight movements, cryptic statements, and radio communications. Many of the signals originally used by the SPARTAN-IIs were taught to the SPARTAN-IIIs by Lieutenant Commander Kurt Ambrose due to his past as a SPARTAN-II.

Oly Oly Oxen Free
Oly Oly Oxen Free is a six-note, six-beat tone used as an all-clear code and the Spartan-IIs' best-kept secret. Virtually no non-Spartan knows it; the only known surviving non-Spartans being Cortana and Doctor Halsey, both close to the Spartans' "family". The Spartans learned it from their AI instructor Déjà on Reach when they were younger and have been using it ever since. This allows the Spartans to use it with guarded impunity over the COM to make others aware of their presence, location, or as an all-clear signal. Thus, the signal was extremely important to each Spartan; they would rather die than give up the significance of the tone, which could potentially be used to betray or endanger their teammates. Spartans would either just whistle the tone or would whistle it and shout "Oly Oly Oxen Free" after. The proper counter-response was "Oly Oly Oxen Free, All out in the free, We're all free." The phrase Oly Oly Oxen Free was once used by children playing hide-and-seek, which meant that the game was over and they could safely come out of hiding.

"Spartan smile"
Having grown up as soldiers, the Spartans kept their emotions to themselves, always controlling bursts of emotion. The closest thing to an emotional symbol is the "Spartan smile," used in place of a smile. The smile consists of a quick swipe across one's own faceplate or a teammates with two fingers. The former way was usually used in place of the latter. Variations of the gesture can also be used to convey other messages or emotions—to welcome someone, show respect or bid farewell, as seen when Lucy-B091 made a two-finger gesture over Kurt Ambrose's faceplate.

Open COM
The Spartans signal to one another to open private COM frequencies by the flick of a finger. It is a move performed only in non-combat situations, when the Spartans can pay attention to each other's movement. This way they can communicate with one another without any unintended people hearing the conversation.

"Attention!"
The Spartans will click a COM channel twice to get the attention of their teammates if they need assistance. Recent improvements in Covenant sensor technology have made this gesture increasingly impractical, as Covenant will be made aware of a Spartan's location if that Spartan uses the COM in the presence of a Covenant vehicle.

"Relax"
The Spartans sometimes console one another non-verbally with a simple bump or gesture of the shoulder. They have become used to their MJOLNIR armor, so each move they make is deliberate. Hence, the gesture is easy to recognize and understand.

"Trouble ahead..."
A Spartan scout may signal that there is trouble ahead with a slight shake of the head from side to side.

"Stay cool"
A short lateral cut with the hand across the chest or mouth area signals to stay calm.

"Inspect armor"
By making a circle in the air with one to two fingers to turn around, a Spartan signals that they want to visually inspect another Spartans armor. Even if the computer diagnostics report everything as fine, Spartans don't take chances with their armor or any other machinery and still visually inspect each others' armor.

"Come forward"
In combat, Spartans motion one another forward by flashing an index finger twice, sometimes two fingers are used for this gesture.

"Wait"
Spartans tell one another to wait by flashing an amber acknowledgment light twice on their HUDs.

"Friendly approaching..."
On the battlefield, verbal communication could risk giving away one's position. Therefore, Spartans inform allied positions that they are approaching by winking their acknowledgment lights green twice.

"Freeze"
Slowly making a fist signals to tell a Spartan team to freeze.

"Unknown ahead"
Spartans on patrol who spot something ahead that is not immediately discernible as ally or enemy will signify it to their teammates by making a hand signal with a thumb pressing into the palm and the other fingers inwardly curled.

"Fall back"
Spartans signal one another to fall back immediately by winking three red acknowledgment lights on their HUDs.

List of appearances

 * Halo: The Fall of Reach
 * Halo: The Flood
 * Halo: First Strike
 * Halo: Ghosts of Onyx