Semaphore Flags

"Semaphore Flags are a system for conveying information at a distance by means of visual signals with hand-held flags, rods, disks, paddles, or occasionally bare or gloved hands. Information is encoded by the position of the flags; it is read when the flag is in a fixed position. Semaphores were adopted and widely used (with hand-held flags replacing the mechanical arms of shutter semaphores) in the maritime world in the early 1800s. Semaphore signals were used, for example, at the Battle of Trafalgar. This was the period in which the modern naval semaphore system was invented. This system uses hand-held flags. It is still used during underway replenishment at sea and is acceptable for emergency communication in daylight or, using lighted wands instead of flags, at night.
Wig-wag signaling (or wigwagging) uses two flags for signaling, in a method similar to semaphore, but by opening and closing the sign, the Morse code equivalent of dots and dashes are used to convey the message. It was used in US Civil War times. A signal corpsman commonly stood on a platform about 6–10 feet off the ground, signaling to other units. The bright orange red and white flag made a primary target for the enemy.
The newer flag semaphore system uses two short poles with square flags, which a signalman holds in different positions to signal letters of the alphabet and numbers. The signalman holds one pole in each hand, and extends each arm in one of eight possible directions. Except for in the rest position, the flags cannot overlap. The flags are coloured differently based on whether the signals are sent by sea or by land. At sea, the flags are coloured red and yellow (the Oscar flag), while on land, they are white and blue (the Papa flag). Flags are not required, they just make the characters more obvious.
The Heliograph was a simple but highly effective instrument for instantaneous optical communication over 50 miles or more in the 19th century. Its major uses were for military and survey work. It was still in serious use at least up to 1935, for example by Glubb Pasha's Arab Legion in Palestine.
The heliograph sent its signals by reflecting sunlight towards the intended recipient with a mirror or mirrors, the beam being keyed on and off with a shutter or a tilting mirror, allowing Morse code to be sent. Heliographs were used by the armies of several countries during the late 1800's; they were highly popular with British forces in India because of the dependable sunlight.
The distance that heliograph signals could be seen depended on the clearness of the sky and the size of the mirrors used. Obviously a clear line of sight was required, and the earth's surface is curved, so the highest convenient points were used. Under ordinary conditions, a flash could be seen 30 miles (48 km) with the naked eye and much farther with a telescope. You might think that reflecting a beam to hit a target 30 miles away would require some precision optical alignment- fortunately this is not so because of the finite size of the sun's disc. The maximum range was considered to be 10 miles for each inch of mirror diameter; mirrors varied from 1.5 inches to 12 inches or more.
Heliographs could be used with moonlight, but at much reduced range.
Speed was 5 to 12 words per minute, depending on the Morse skills of the operators."