Building Industry In Old Times Chapter 382

The difficulty of wired telegraph is the laying of lines. When subsequent projects mature, many developments can be made.

The wiring principle of a telephone is generally the same as that of a wired telegraph. The only difference is the terminal principle.

Globally, wired telegraph became popular in the 1850s, and the telephone was invented in the 1870s.

As for the Chinese in history, these two were introduced into the Central Plains almost at the same time.

In the 1880s, when Li Hongzhang was vigorously laying wired telegraph lines, telephones also appeared in the Qing Imperial Palace.