In this case, the term semaphore is equivalent to optical telegraph.
The separation isn't completely clear, but take a semaphore like a basic tool that produces signals with a strong predefined signification, like a red light in a highway traffic light. The optical telegraph have a basic signification on their symbols, like letters or numbers, but a wide range of meanings, like the message transmission.
The separation isn't completely clear, but take a semaphore like a basic tool that produces signals with a strong predefined signification, like a red light in a highway traffic light. The optical telegraph have a basic signification on their symbols, like letters or numbers, but a wide range of meanings, like the message transmission.
Take a look to the wikipedia information: https://en.wikipedia.org/wiki/Optical_telegraph