This specification defines general requirements and test methods for waveguide to coaxial adapters. It includes terms and definitions, design and construction, ratings and characteristics, climatic categories, IEC type designation, requirements and test methods, quality assessment, markingÿ and etc. It provides the basis for establishing the sectional specifications for various waveguide to coaxial adapters. This part applies to waveguide to coaxial adapters (short name adapter). For the purpose of this specification, according to ends, adapters are classified as the following: Class `!ÿWaveguide to coaxial connector adapter, waveguide at one end, and coaxial connector at the other end; Class a!ÿWaveguide to coaxial cable adapter, waveguide at one end, and coaxial cable at the other end; Class b!ÿWaveguide to coaxial cabled connector adapter, waveguide at one end, and coaxial cabled connector at the other end. According to whether the inner conductor probe of coaxial end is connected with the inner wall of waveguide cavity or not, adapters are classified as the followingÿ Connected adapter: Inner conductor probe of coaxial end is connected with inner wall of waveguide cavity; Disconnected adapter: inner conductor probe of coaxial end is disconnected with inner wall of waveguide cavity.