Low-pass filter combined subrack

The utility model discloses a combined subrack of a low-pass filter. A plug-in box belongs to the technical field of plug-in boxes, and comprises a box body, a first heat conduction plate is fixed atthe upper part in the box body, a second heat conduction plate is fixed at the lower part in the box body, and the top of the first heat conduction plate and the bottom of the second heat conduction plate are connected with heat dissipation fins extending to the outside of the box body; a fixed block, a pull rope, a protective plug and a sealing gasket are arranged; when the input port and the output port on the plug-in box need to be protected, the plug-in box is opened. A user plugs the protective plug into the input port and the output port through the pull rope; meanwhile, in the pluggingprocess of the protective plug, the sealing gasket on the outer surface of the protective plug is extruded to deform; the protective plug is arranged in the box body, the protective plug is connectedwith the input port and the