The present invention relates to a method for selecting an appropriate mode when performing a new broadcast, such as a 3D stereo broadcast, a UHDTV broadcast, and a multi-view broadcast, among others, while maintaining compatibility with existing broadcasting channels in an MPEG-2-TS format for transmitting and receiving digital TV, and to a method for recognizing a descriptor. The assembly is to be located in a duct to screen a flowable substance passing in a direction. The arm may be coupled to a connection clip that can grip a selected line. The system portion includes first beam deflection structure by which the imaging beam path of the imaging optical system is deflectable in a direction along the pitch axis. A latching mechanism that contacts the cover at two points distributes stresses better than where the latching mechanism only contacts the cover at one point. The low voltage DC power is further controlled by a DC-DC converter to generate controlled DC power.