The PBC-L475 can be used in either Sum-to-Mono mode or Mono-to-Stereo Split mode. The transformer provides isolation and balancing for audio level signals. The card is very simple to hook up and the frequency response is great – it’s almost a flat line from 30 Hz to over 20 kHz. The unbalanced audio can be connected with screw terminals or RCA plugs. It comes with a strip of foam tape for mounting.