If both serial ports are disabled and you can not connect via Ethernet, there is one more thing you can try to establish communications. (You may find yourself in this predicament if PORT2 is configured for an RP240 with the DRPCHK command, and PORT1 is disabled because of the NTFEN setting.)
1. Connect your serial cable to port2.
2. Start Motion Planner and open a terminal window.
3. Cycle the power on the unit while holding down the B key. This should put your controller in flash mode. You can confirm this by pressing the return key and observing a colon instead of the regular ">" prompt on the screen.
4. Download the OS by selecting the download OS option in the communication tab. This should wipe the memory and return the unit to factory settings.