The MCL-USB adapter (radio) is an interface converter for USB to radio. It can be used to connect FDnet/C-NET devices to a PC using a serial protocol (MCL). The adapter is used for the firmware update or for operation. The adapter is used, e.g. for floor repeater display FT2011-A1, floor repeater terminal FT2010-A1, line tester FDUL221, etc. (in the future other FDnet/C-NET devices possible).