usb cdc 클래스들에 대한 설명 출처 : http://www.jungo.com/st/embedded_usb_cdc.html CDC-ACM (Abstract Control Model) allows any communication device to provide a serial communication interface (e.g modem devices that send and receive AT commands). CDC-ECM (Ethernet Networking Control Model) offers device manufacturers to interface as a standard NIC (Network Interface Card) device. This interface is usually a..