Diver down flag. A diver down flag, or scuba flag, is a flag used on the water to indicate that there is a diver below. Two styles of flag are in use. Internationally, the code flag alfa/alpha, which is white and blue, is used to signal that the vessel has a diver down and other vessels should keep well clear at slow speed.
Familiarize yourself with some friendly network cables and take a closer look at common types of network media, including twisted-pair cable, coaxial cable, fiber-optic cable, and wireless.
Answer Wiki. Most commonly used for data communications, coaxial cable is a type of TV cable with multiple layers. The innermost section is simply copper wire with insulation (dielectric) surrounding it. Next it is covered in copper mesh (foil or braided conductor) and covered with an outer insulation jacket, which grounds it.