In the context of a CCTV camera TVL (TV Lines) refers to the horizontal resolution (the maximum number of vertical lines the camera can resolve) of the CCTV camera. TV Lines are the standard measure of an analog TV's Resolution. Rather than represent discrete locations on a grid, as Pixels in a digital Frame do, TV Lines indicate the maximum number of identifiable changes that can be produced along a single (horizontal) Scanline of an analog TV.