Originally Posted by
JD-EE
HN 39 asks, "Which computer?"
At the very least the wee little computer that drives the FDR surely knows. If it knows then its source can also route that data where ever else it is needed.
I suppose you are referring to the FDIU (flight data interface unit).
It's barely a 'computer'... the French term 'ordinateur' would be better.
It doesn't 'know' anything, and it doesn't 'think', it just converts and formats the multiple original AC and DC signals and digital info to a single formatted digital data stream (ARINC 717) which is then recorded by the FDR.
The link below is litle more than advertising, but may give you a few hints.
Teledyne FDIU