What is a flasher input. I just purchased the Marantz SR5010 and i found a input jack in the back labelled "Flasher" in plus an "IR".

What wold this be used for? I read something that it is for legacy Marantz products?

Anyway… any info would be appreciated.
If your Marantz unit is in a cabinet where there is no line of sight for the remote, the "flasher unit" is put outside the cabinet to allow the remote to work.

It's a remote...remote sensor.