Cooling-fan-free system module

A cooling-fan-free system module, comprising:

• a housing unit including a front case and a rear case assembled together to define a receiving space therebetween, said rear case being made of a highly heat conducting metal material and having an inner side facing toward said receiving space and a back side facing away from said receiving space;
• a circuit module received in said receiving space, said circuit module including a circuit board, and at least one heat-producing element mounted on and electrically connected to one side of said circuit board facing toward said inner side of said rear case;
• and
• a heat radiating unit including at least one insulating heat conductor bonded to said inner side of said rear case at a position corresponding to said at least one heat-producing element, so as to transfer heat produced by said at least one heat-producing element to said rear case, and at least one heat radiating member integrally formed on said back side of said rear case and consisting of a plurality of radiating fins,
• wherein said rear case is further provided at a rear lower edge and a rear upper edge with a first and a second cutaway portion, respectively, to communicate said receiving space with an outer side of said housing unit;
• and
• wherein said circuit module further includes at least one signal transmission element mounted on and electrically connected to said circuit board, and at least one bracket assembled to an inner lower side of said housing unit:
• said bracket being provided with at least one opening corresponding to said at least one signal transmission element, and at least one aperture communicating with said first and said second cutaway portion.