Hi Franco,
it will never work with RRC-1258 MKII because these units are device interfaces
and not host interfaces like a PC.
A converter from USB to Serial will also not work because the Expert-2k is not a host either
but a device that needs to be connected to a PC.
The only thing that works but untill today I dont get the display updating quickly enough
is a myUTN-50 from SEH, commandos are working ok but display is not,
Also USB via Ethernet from Fabulahtech or Eltima (both are software packages) are working
but then you need a PC.
Keep you informed
Guy ON4AOI