A connection system for electrical, signal and/or data installations, comprising: - one or more multilayer flat cables with several parallel conductive tracks arranged between a first layer and a second layer of insulating material forming two external surfaces of each of the one or more flat cables, - a connection box made of insulating material, and - installation mechanisms for the realization of installations comprising: electronic components and a printed circuit, wherein the electronic components are mounted on the printed circuit provided with conductive tracks and housed in the connection box, said connection box having lateral windows for inserting one of the ends of the one or more flat cables and for connecting its conductive tracks to the conductive tracks of the printed circuit of the corresponding mechanism; characterized in that: • the first layer of insulating material of each of the one or more flat cables is made of a plastic material resistant to bending and of low resilience, which presents on its external surface a series of transverse recesses, distributed along the flat cable which facilitate its winding and define break zones for removing a portion of said first insulating layer and for defining at the ends of the flat cable a connection end portion, directly able to be coupled to the connection box, and in whose connection end portion the conductive tracks are exposed to the first outer surface of the semi-rigid flat cable, • the second layer of insulating material of the flat cable is made of a flexible polymer; • the connection box internally comprise flexible legs formed in the insulating material itself of the connection box, and acting on the second insulating layer of connection end portion of the flat cable by pressing the conductive tracks of the flat cable against the conductive tracks of the printed circuit of the mechanism. - one or more multilayer flat cables with several parallel conductive tracks arranged between a first layer and a second layer of insulating material forming two external surfaces of each of the one or more flat cables, - a connection box made of insulating material, and - installation mechanisms for the realization of installations comprising: electronic components and a printed circuit, wherein the electronic components are mounted on the printed circuit provided with conductive tracks and housed in the connection box, said connection box having lateral windows for inserting one of the ends of the one or more flat cables and for connecting its conductive tracks to the conductive tracks of the printed circuit of the corresponding mechanism; characterized in that: • the first layer of insulating material of each of the one or more flat cables is made of a plastic material resistant to bending and of low resilience, which presents on its external surface a series of transverse recesses, distributed along the flat cable which facilitate its winding and define break zones for removing a portion of said first insulating layer and for defining at the ends of the flat cable a connection end portion, directly able to be coupled to the connection box, and in whose connection end portion the conductive tracks are exposed to the first outer surface of the semi-rigid flat cable, • the second layer of insulating material of the flat cable is made of a flexible polymer; • the connection box internally comprise flexible legs formed in the insulating material itself of the connection box, and acting on the second insulating layer of connection end portion of the flat cable by pressing the conductive tracks of the flat cable against the conductive tracks of the printed circuit of the mechanism. • the first layer of insulating material of each of the one or more flat cables is made of a plastic material resistant to bending and of low resilience, which presents on its external surface a series of transverse recesses, distributed along the flat cable which facilitate its winding and define break zones for removing a portion of said first insulating layer and for defining at the ends of the flat cable a connection end portion, directly able to be coupled to the connection box, and in whose connection end portion the conductive tracks are exposed to the first outer surface of the semi-rigid flat cable, • the second layer of insulating material of the flat cable is made of a flexible polymer; • the connection box internally comprise flexible legs formed in the insulating material itself of the connection box, and acting on the second insulating layer of connection end portion of the flat cable by pressing the conductive tracks of the flat cable against the conductive tracks of the printed circuit of the mechanism.