can routerboard 150 can be used for ppp over the serial0

Hi there,

i want to use the serial0 instead of Console for PPP over serial attached ISDN terminaladapter
When trying to change serial0 settings over the Winbox from no handshake to hardware
i get a “Couln´t change Port - can not change port settings (6)” error message!

Router OS is 2.9.38!

regards, Klemens