What is the purpose of the unmarked expansion slot on the back of the CS6X and CS6R? It is illustrated but there is no mention of it in either the User or Service manuals, except for the part numbers of the cover and screws. I can only surmise it may have something to do with the Yamaha MIDI/LAN interface. Thanks for your time.
After five more minutes of searching, I found that the slot is for the mLAN8E expansion card, which provides three Firewire and one 1394 port for digital connections. Very neat. If I get the CS6R I am aiming for, an mLAN8E might be a worthwhile addition.