Abstract: The invention concerns an interface unit (50,80) with an electrical interface (40, 110) for connection to an electrical USB cable, an optical interface to connect to at least one optical waveguide for sending and receiving of optical signals, and a conversion unit that is capable of converting the signals D+ and D? at the electrical interface to optical signals for output at the optical interface, and that is capable of converting the optical signals from the optical interface to electrical signals and output these signals as D+ and D? at the electrical interface According to the invention it is defined that the conversion unit has an analyzing unit (210) for separation of the useful signals (NS) and the control signals (SS) that are contained in the D+ and D? signals, and that the analyzing unit is subsequently connected to a recovery unit (220, 400) that generates at least two electrical driver signals for subsequent sending units out of the useful signals (NS) and the control signals (SS), and that the sub