Well then next time I'll include a link to the sources Im working with. There is no DeviceDisconnect, DeviceConnect functions in them. Anyway, my concern was with respect to the thread title, and I now see I was the victim of a blunder (made by me). Now I see that the host interrupts the device (activates the INT0 pin) each SYNC. I'd forgotten the interrupts are set to edge triggered, positive edge. It is the first K in the SYNC that triggers the interrupts if unmasked and global enabled. This changes everything in my perspective.
By this time I'm busy with the usb_control_msg() function of libusb (linux). I see its parameters nearly match the ones in table 9-2 of USB specications 1.1 and 2.0, which by now I know well, with the exception of... What a pity! The bmRequestType is 0xC0, with the result that the type is type=vendor, and those specifications only cover standard device requests!
By this time I'm busy with the usb_control_msg() function of libusb (linux). I see its parameters nearly match the ones in table 9-2 of USB specications 1.1 and 2.0, which by now I know well, with the exception of... What a pity! The bmRequestType is 0xC0, with the result that the type is type=vendor, and those specifications only cover standard device requests!