Yes something needs to process the signal to a 0-5v output. With the LC-1 u you have some software too to log without an Xcal 2 if you want. Plus you can set up the actual outputs, say to fine tune them. Or use the WBO2 as a NBO2 also.
The Xcal 2 has two analog inputs. One set up for 0-1V and the other for 0-5v. There are two others too but there is no documentation on them that I am aware of.