What does the telegraph code mean?

Similar to the computer binary, 8-bit binary represents a letter, 16 represents a word, and 32 bits represent a double word. . . . Telegrams also have only two on-off states, similar to binary, and the universal "-"is disconnected from "0". For example, in wartime, there are several sets of telegraph codes that can be changed at any time. There are full-time personnel to code, such as the Chinese character "I", which can be compiled into "-0-0 00-0-0".