Telegraphy the sense of a system that can transmit arbitrary messages over arbitrary distances. Lines of signalling relay stations can send messages to any required distance, but all these systems are limited to one extent or another in the range of messages that they can send. A system like flag semaphore, with an alphabetic code, can certainly send any given message, but the system is designed for short-range communication between two persons. An engine order telegraph, used to send instructions from the bridge of a ship to the engine room, fails to meet both criteria; it has a limited distance and
General Service Code of the communications officers. General Service Code General Service Code is a code that was used during the American Civil War. The code uses one flag or two torches. The flags come in three color schemes: a red square in the middle of a white background, white on black, or black on white. The flag that is used at any time depends on the visibility. The flags come in three sizes: two feet by two feet, four by four, and six by six. The 2x2 flags are used in battle to send messages back to headquarters and to send back