The RB-BL2 is a bi-directional stereo unit for interfacing domestic or semi-pro unbalanced equipment to professional balanced line levels, and vice-versa.
 
The two XLR-3 electronically balanced inputs have an impedance of 20kΩ bridging and are routed to two unbalanced RCA (phono) outputs with an output impedance of <50Ω.

The two RCA unbalanced inputs have an impedance of 20kΩ and are routed to two balanced XLR-3 outputs with an output impedance of <50Ω. All connections are on the rear panel.

The output gain can be adjusted for left and right channels by using pre-set potentiometers accessible through the rear panel.