Could you give me more information on the meaning of the +4 dBu and -10 dBV settings and how they would vary with impedance matches of external devices?
The +4 dBu setting is used with differential (balanced) I/Os and the -10 dBV is used with single-ended (unbalanced) I/Os. Output impedance is 300 ohms per leg, so if you are interfacing with a balanced device the impedance would be 600 ohms and you would set the jumpers to +4 dBu. A single-ended device would be 300 ohms and you would set the jumpers to -10 dBV. Typically, professional devices would use balanced I/Os and consumer devices would use single-ended I/Os.
