> May I ask what drives the USBSERVICE interrupt?
The USB module itself generates many different interrupts.

> Also I would like to use DT_INTS-18.bas in the program as well
> but I don't understand how to use the interrupt hook handler,
> and could not find any example of it.
That is not possible with USB_ASM_Service.pbp.
All interrupts used with the "Hook" can only be ASM (assembly language) type interrupts.

> Or... is there a way to turn DT_HID260 into a DT_CDC260?
No, but I could write a DT_CDC program. If I ever get my computers and internet access at home.