Every reference I've looked at for Arinc429 specification has something like this:
Okay, pretty simple. There is only one transmitter and up to 20 receivers.
However, the name of the SDI (source/destination identifier) field is confusing me.
It implies that there can be multiple transmitters by allowing you to define "where" the message has come from being sent to a receiver.
Is that simply useful for debugging purposes? It might make sense if there some sort of data recorder listening to all the arinc buses.