Signal aspect and Indications of distance, block, and interlocking signals are shown in the special instruction.
This can be found in the 9.0 block system rules from 9.1, which explains the signal aspects are identified by the position of semaphore arms, the color of lights, position of the light, flashing of light, or any other combination.
The aspects are classified as marker plate, number plate, letter plate, or marker light, as written in the rule book.
This special instruction is made for aviation employees, railroad users, truck drivers, and other people who need to know the rules. It is very important to read the instructions as it will help one avoid making a mistake and being punished for lack of knowledge.