An avionic system for an aircraft including at least two pieces of equipment which can exchange information by means of at least one electrical bus for simultaneous bidirectional communication, in which the information can be exchanged between pieces of equipment via an optical bus that can be connected to the electrical interfaces of the equipment. The optical bus of the avionic system includes at least one optical cable having at least one optical fiber and, at each end, a connector having means for converting electrical signals into optical signals and means for converting optical signals into electrical signals. The optical bus is connected to the electrical outlets of existing equipment.