Hi Jack; Just a quick note to let you know I now have DXBase 2004 up and working with both rotor controls. I replaced my ISA serial port card with a PCI card and everything is working fine. I don't know why the the ISA card would work with DXBase 2002 but would not with 2004. Anyway it is operational. I want to thank you and many others for the advise and suggestions. 73, Len, K6ANP