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.
March 31, 2015. 1  RF cables are a type of coaxial cable that is used to send radio frequency signals. 2  RF cables can be identified by the connectors at the end of the cables. 3  RF are the standard cable inputs on TVs; almost all TVs have an RF input.  RF cables provide lower video quality than newer cable connections like HDMI and DVI.