The interface is based on a USB hub with three USB ports. On the PC side, the interface is connected only with one USB cable, which serves for data transfer and provides power. The whole interface fits inside the standard casted aluminum housing with outline dimensions of only 100x50x25mm.The interface is modular and provides several different configurations according to specific needs. There are three ports on the USB HUB. The ports 1 and 2 are always available for additional modules, and on the port 3 is shared either the CAT / PTT / CW interface that is already installed on the hub itself or the auxilary USB connector for additional external devices. The sound and CAT module can be connected to USB HUB ports to expand the functionality of the interface.