the narrow band is attached to my bosch ecu, and i tapped into the signal line reading the voltage from it.
you can tell rich/lean but nothing else...
here you can see the output logged:
its a quick 1-2 gear run logged with the multidisplay, showing the lambda control for the first seconds (rich/lean cycle) and then rich during full throttle and lean when letting off.
on some VW´s we are running the LC-1 as a replacement for the narrow band sensor, with its 2 outputs (one programmed to simulate the narrow band for the ecu) and the 2nd to display it.
thats working quite well, all cars pass the emission tests 
having access to the gases it nice, would be nice to see how accurate for example the LC-1 is compared to a Bosch Ecu 