This makes sense. Yes, the signal is +/-12KHz at 1.2K BAUD.
If I record say a second of data in zero span, it looks like it’s all there. Which leads me to believe that is really is a limitation of the software and not the hardware.
I am curious why there is a limitation like this? It looks like you are pretty close to being able to just pull the digital data directly. Of course, then I would want to store the digital data rather than the copy to the clip board.