Hi. Downloaded the VISA 3.1, and yes, now I can detect my Interrupt endpoint for USB:) Thanks! Still one problem though.. In VISAIC, I can wait on the USB interrupt, and it returns the interrupt data from the device fine in the VI_ATTR_USB_RECV_INTR_DATA. I then try to use the Get_interrupt_data.vi in Labview, after enabling the event. But I get the message: "attribute not supported by the reference.." I can't see any other way to retrive the interrupt data stored.. From the event properties I can read that the number of bytes stored is correct, but I am unable to access them. Please help!?