The connection is serial. On RA Monitor the port settings are locked to the only mode the 2650 uses - 9600 baud, 8 data bits, no parity, one stop bit - so there is nothing to configure beyond picking the COM port and pressing Connect.
A modern laptop with no legacy serial port takes a USB-to-serial adapter, and the software re-scans for ports while it is running, so you can plug the adapter in after starting the application.
If the PC is not next to the console, a wireless data link carries the connection instead of a cable. That is the same idea as the trackside printer: the port moves, the settings do not.
When something is not connecting, the status indicator tells you which end is at fault before you start swapping cables.