Signaaliketta

Signaaliketta, often translated as signal disk or semaphore disk, is a signaling device used historically to transmit information visually over distances. It typically consists of a flat disk, often made of metal or wood, with a movable arm or colored panels that can be positioned to represent different letters, numbers, or pre-arranged codes. The primary advantage of a signaaliketta was its simplicity and effectiveness in clear weather conditions.

The operation of a signaaliketta involved one person manipulating the device and another observing from a distance, usually with a telescope. By changing the position of the disk's components, specific messages could be spelled out or indicated. This method of communication was particularly useful in military contexts, for railway signaling, and in maritime communication before the advent of more advanced technologies like wireless telegraphy. The effectiveness of the signaaliketta was highly dependent on visibility; fog, rain, or darkness rendered it unusable. Despite its limitations, it served as a vital communication tool for a considerable period, contributing to the organization and coordination of activities across distances. Its legacy is found in the development of more sophisticated visual signaling systems and its place in the history of communication technology.