SAE AIR1189A

Electrical and electronic systems of modern aircraft are becoming increasingly more complex, requiring the interchange of more and more information within and among these systems and subsystems. At the present time, most of this information is exchanged by use of individual wires dedicated to the communication of each signal. However, many advantages are achievable by utilizing a common medium to communicate multiple signals. This concept is termed multiplexing. It is the purpose of this AIR to define certain characteristics that should be incorporated in aircraft multiplexing systems. These characteristics represent those that have gained general acceptance by industry as being desirable for multiplexing systems. As others are defined, they will be included in revisions of this AIR. All electrical and electronic signals within an aircraft are potential candidates for multiplexing, although the determination of whether or not they are multiplexed is a matter for individual system consideration. However, those signals that are selected for multiplexing preferably should conform to the characteristics included in this AIR.