Disklavier

Hi I wanted to check about the requirements needed on my control unit DKC500R (in a mpx1) to be able to use 1) the dcd1 or 2) the dkc850

There is that specificity which I have found:

"New Control Board. Unless your Disklavier was previously upgraded to 8 Mb of memory so it would play SmartKey, or has the EMK1 module, it will also need a new control board.  If your system is a MarkIIXG (with no EMK1 or Smartkey) and has the DKC500R Control Unit, then you will need the new control board #V2211700.  If you have a MarkIIXG (with no EMK1 or Smartkey) with a DKC500RXG Control Unit, then you will need the new control board #V2520400.  If your Control Unit has a W in the model number, you do not need a new control board.  This new control board is available from your Yamaha dealer for about $350 plus installation.  It also upgrades your current XG tone card to allow you front panel access to 480 instrumental voices instead of 128.
http://www.carolrpt.com/pianosmart.htm

I was told that to prepare the DKC500R for  the dcd1 I need the new control board but for the DKC850 I dont need it: is that so ? and...

If I get the EMK1 module  installed in my DKC500R then according to the previous explanation (http://www.carolrpt.com/pianosmart.htm) I would not need a new control board...

I just want to be sure, if getting an EMK1  is enough for pianosmart with a DCD1...or not !

Thanks