Vane Signals

Vane signals are a method of long distance communication used by the militaries in Deejs and Kealriv. It consists of two 2x3 grids, though most signals can be relayed only using one grid. The second grid is used for redundancy and for more complex signals. Each portion of the grid has a vane similar to a windmill vane which is controlled by a rope and pulley system. They can be placed in either an open or closed state. Messages are relayed by flashing the different patterns in a vane tower, or the same effect can be used with window shutters to leave static messages. Vane towers only work when there's a visible line of sight, and typically only during the day. However, some units have been experimenting with using lights to relay messages in the dark. Using the pulley system, an operator can open and close multiple vanes at once. When only one grid is needed, the second is flashed with the same pattern after a short delay. Repeated letters in a word are conveyed by either using a duplicate symbol or flashing the same pattern on the first vane. The vanes are made from either metal or wood. Some are painted to make the open and closed status clearer. When two towers need to communicate with each other, one will flash a "START" message and wait for the other tower to flash "READY". At that point, the first tower will begin the message and finish it with "END". To reply, the second tower will flash "START" and wait for "READY". The coded patterns also have gained traction in the military through written messages. A variant system uses dots and vertical lines. Small templates exist to help people line up their dots. Since most messages can be sent within a single grid, the patterns are written out one after another. A message requiring both grids has a single vertical line separating the two panes, and the dots to the left and right are meant to be read as a single unit. While Deejs and Kealriv use the same system, their militaries use different patterns. Also, in wartime, the patterns are subject to change. Officers are issued signal books to be able to interpret the messages. These patterns may be updated multiple times throughout the war, so there have been instances where operators use different books. Aware of this possibility, conflicting patterns are never mapped onto each other in adjacent versions. That is, the signals for "ATTACK" and "RETREAT" will never be the same. Most officers and operators keep multiple editions of the signal book, and some will intentionally use old editions to further obscure their own messages except to the intended target.