The present invention consists of or includes an inlet device, of the valve type, used in a Central Vacuum System (CVS) and built into the skirting board, namely in the kitchen of a house. The function of the device is to collect dust and small debris with the aid of a broom into the entrance of this CVS, by means of a micro-switch activated CVS mechanism located in the skirting board, so as to avoid the use of a vacuum cleaner or vacuum tube also connected to the CVS. The device can comprise: a base body which can be assembled on the wall at the height of the skirting board; a cover which engages in the base body; an unlocking button which disengages the cover; a sealing strip which is glued to the base body; a micro-switch which engages in the base body; a helical torsion spring engaged in the cover, by means of a pin, which causes the cover to open in relation to the base body. By pressing the unlocking button the user causes the opening of the cover, which activates the micro-switch, which, in turn conveys an electric signal to the CVS so that it stars to vacuum.