I tested your UTD-10 USB -DMX Cable with my RDM Controller software. The dongle acts like an FT232 interface. So DMX transmission and RDM communication are OK.

The issue comes with a universe size larger than 63Bytes and not equal 513 bytes: The FT_Write command returns FT_OK and all bytes are written. But the OUT-LED stays off and DMX fixtures are indicating a signal loss. This means that the UTD-10 cannot be used for firmware updates and that longer RDM requests (>63 bytes) won't be sent.

My other FT232 interfaces do not have this issue when running with the same test software. Could you please check?

ScrollBar1 goes from 50 to 513. Timer1interval is 100ms.

best regards

Dr.-Ing. Hendrik Hoelscher

if (FT_Open(0, &ftHandle) == FT_OK)                          //<- optimize to open specific device (and not every FTDI...)
   {
   FT_ResetDevice(ftHandle);
   FT_SetBaudRate(ftHandle, 250000);                  //250kBaud
   FT_SetDataCharacteristics(ftHandle, FT_BITS_8, FT_STOP_BITS_2, FT_PARITY_NONE);
   FT_SetFlowControl(ftHandle, FT_FLOW_NONE, 0, 0);
   FT_Purge(ftHandle, FT_PURGE_RX);                          //clear buffer
   FT_Purge(ftHandle, FT_PURGE_TX);
   FT_SetTimeouts(ftHandle, 60, 60);                         //Tx, Rx
   Timer1->Enabled= True;
   LogMemo->Lines->Add("OpenRDM interface initialized!");
   }

void __fastcall TForm1::Timer1Timer(TObject *Sender)
{
FT_SetBreakOn(ftHandle);                                        			
FT_SetBreakOff(ftHandle);
ULONG ByteCnt;
DmxField[3] += 1;
if (FT_Write(ftHandle, &DmxField, ScrollBar1->Position, &ByteCnt) != FT_OK)       				//transmit universe
   {
   Form1->LogMemo->Lines->Add("no OpenRDM interface found");
   Form1->Timer1->Enabled= false;
   return;
   }
}