AD6645  evaluation board


I have purchased AD6645 evaluation board and trying to get data from it,

I want to ask some questions. The board is equipped according to the AC coupled analog input configuration. Should I terminate the analog input SMA connection by R2=50 or 60.4 Ohms as indicated in AD6645 datasheet page 18, figure 40 and page 22 ? Do I need to disconnect R15 or can I use them together? The board has R15 connected and R2  not connected.