I am working with device with HID keyboard feature but not exactly keyboard. First I have implemented USB keyboard functionality with sample code supplied by MCU vender(ATMEL) but speed was too slow. There was also generic USB HID device sample code so I have tried to use it but I couldn't convert it to HID keyboard. I comrad said that only some descriptor modification will change it so I tried but I couldn't. Is it true that only descriptor change can do this or should I modify some other parts? descriptor I have changed is product id, interface subclass, interface protocol, number of endpoint etc.. I have examined descriptor of ready-made product by USB monitor program. I know little about USB and I don't have time to look into USB protocol. Please answer.