DB
The decibel is a logarithmic unit of measurement that expresses the magnitude of a physical quantity relative to a specified or implied reference level. Since it expresses a ratio of two quantities with the same unit, it is a dimensionless unit. A decibel is one tenth of a bel.
The D-subminiature or D-sub is a common type of electrical connector used particularly in computers. Calling them "subminiature" was appropriate when they were first introduced, but today they are among the largest common connectors used in computers. A D-sub contains two or more parallel rows of pins or sockets usually surrounded by a D-shaped metal shield that provides mechanical support and some screening against electromagnetic interference. The D shape guarantees correct orientation.
