This indicates that the Digi Device Server (i.e. a PortServer) is not setup properly to use for RealPort.
By default the Device Server is set to set port dev=term this means that DDR-RTS are high and the PortServer sends a login. This must be changed for RealPort to a passive setting which will not generate a login:
set port dev=prn auto=off range=(port_numbers)
The unit should be rebooted for this change to take affect:
This will prevent the Device Server from generating a login. The port will be in a neutral state for RealPort to control.
Aug 23, 2017