The utility model discloses a
cable modem, including casing, circuit board, is equipped with main
chip and upstream and downstream
signal processing unit on the circuit board, and downstream
signal processing unit is connected with modulation
signal interface, still includes the fin, and the fin fixedly arranged on the circuit board, and the fin includes the contact piece, the connecting piece, the fin of integral structure, and the contact piece is contacted with main
chip, and the connecting piece sets up in the contact piece four weeks to connect the fin, and the connecting piece is set up to the top of shell folding to the fin is set up to the outside folding of shell, and the circuit board on the outer periphery of main
chip is equipped with a plurality of third vent, and the top of shell is equipped with first vent, and the bottom of shell is equipped with second vent. The utility model discloses the structure of fin has the
special design to the space inside casing, has greater radiating area, and the circuit board below the fin is seted up third vent, and third vent and first, second vent cooperate and form the
chimney effect, and it is favorable to better heat dissipation.