DI-2108 digital inputs confusion

DI-2108 digital inputs confusion

I am having some trouble understanding how digital inputs on the DI-2108 using WinDAQ are supposed to work. I only see an option to enable "channel 9" in WinDAQ to enable the digital channels for input, why isn't there a separate enable setting for each channel?

It also looks like all the digital inputs are aggregated into a single channel (9) in WinDAQ, and that some sort of math is done on the aggregate value of all the inputs that is determined by the units per division, and also ranges around a zero point (so we wind up with negative values for the collection of channels). Can you explain why the digital inputs are represented like this, why it is useful and is there a way to represent each input separately like a logic analyzer would (with lines rather than boxes).

Are the threshold values for each channel able to be configured so that I can choose when the DI-2108 decides an input is "on" vs. "off"?

In my setup, I always see channel 4 as "off" (box is not displayed). I do not have that channel's inverting checkbox set, and I do not have anything connected to any of the digital inputs. If I connect a signal to channel 4, I can see that WinDAQ display follows the input, so it seems that the input is working, it's just strange to me that one out of the seven inputs would be different than the others. Is my DI-2108 defective or is there some sort of configuration that I have inadvertently set for this channel?

Does channel 7 exist to be used to monitor an external signal?

The button is channel 0, is there a way to map the button to channel 7?