The invention relates to a device for connecting an item of equipment and two cables, one of which carries electrical data and the other of which carries pneumatic data. The device comprises an electrical socket and a pneumatic socket, both mounted on an item of equipment, an electrical plug secured to a cable, the electrical plug being intended to be connected to the electrical socket, and a pneumatic plug secured to a cable, the pneumatic plug being intended to be connected to the pneumatic socket. According to the invention, when the pneumatic plug is in a connected but unlocked position, the electrical plug cannot be plugged in.