The mc2 communicates over TCP/IP, and has no serial PC connection.
The Rocrail pairing key is fixed and is assembled as follows: (Just for information; No user action is needed.)
(IANA-PEN << 32) + (IANA-PORT << 16) + (NMRA-VID)
Press the GO button on the mc2 after "PA" did appear in the mc2 display.
The mc2 uses the default Z21 UDP port 21105.
For more details see: Roco Z21
The p50x TCP port is 8050.
Set the Host and Port to meet the mc2 to activate the LAN communication.
The P50x command set is the same as the used with the Tams Redbox.