Yes, it comes with SmartLink (3x coax), RS232 and DIN comms cables. I can't remember if it also comes with a coax comms cable, but I think not (which is a bit weird).

MConfig - you need to connect the RS232 to the HD621.

AAC - no idea.

Roon Developer and ex-moderator of this Forum
I am #25 in the HH1 photo of fame.