Peter,
Is there any specific reason you chose RS232 control over Ethernet if the MRX-2 can send commands over the network?
We recommend ensuring the Digi One setup is exactly as page 12 of the attached documentation, as it should always keep the TCP connection established with the processor to avoide the login prompt.
If this does not resolve the issues, could you please take screenshots of how the Digi One is configured? Also, please connect to the processor via "Tools->Terminal", reproduce the issue, then send the command "outboundconnections". After the results are listed, right click on the Terminal window and choose to "save log". Finally, create a support file by clicking on "help->support->create support file" and send all of this information to
hwsupport@lutron.com