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.
The simplest transmission media is a two-wire transmission line. There are two wires insulated from each other, open to free space. This type of media is suitable for connecting equipments that are separated less than 50 meters. This media can support data rate up to a theoretical maximum of 19 Kbps. A two-wire transmission media can directly connect two computers.