Aerospace platforms have been around for decades. Their technologies are outdated legacy but continue to be adapted for use in aerospace, robotics, ground vehicles, industrial control and other applications. Their proven high reliability, fault-tolerant, deterministic capabilities and able to operate in high electromagnetic interference mean they will continue to be used for a long time to come. Legacy buses such as Mil-Std-1553 are here to stay. New aerospace standards, however, are based on Ethernet open architecture which is deployed everywhere. They are not compatible with legacy buses. Older buses operate at much higher voltage. Their protocols are more primitive and often centrally controlled rather than distributed – more parallelism. Working with them is not so easy. Prime developers generally kept the strangle hold on the technologies. Their designers/developers may even no longer exist. New generations of developers do not learn about them as Ethernet is more widely taught. It is a pain point in the industry but also opportunities.

This paper will discuss the applications, technologies of legacy standards such as 1553 and newer Time Triggered Ethernet (TTE) and Time Sensitive Network (TSN) defined by SAE and IEEE for future aerospace networking and other applications. It will also discuss opportunities, technical challenges for bridging new standards into legacy aerospace platforms allowing them to co-exist. Lastly, it will discuss efforts in standard organizations to standardize the interoperability of the legacy buses to newer standards