How to distinguish national defense optical cable

The warning signs of military optical cables are called "warning signs of national defense optical cables". National defense optical cable is the carrier and important customer of information transmission between the party, government, army and people, and it is also the optical cable line for commanding communication of troops and transmitting information to major military regions and military bases by the Central Military Commission. Different from ordinary operators' optical cables, they are absolutely protected. The warning sign of national defense optical cable is to remind that there is a national defense optical cable laying nearby, and absolute approval is required in the warning sign construction area.