Fout and Fout*

Hi I’m just wondering does anyone know the function of Fout and Fout* connected to R2out and R2in respectively of the SP3232 IC in version 1.6 of the DSO Nano? I’m currently trying to simulate the SP3232 IC in Multisim to confirm the plus and minus 5V but am currently getting 0V output on both.

the Fout* is from the output pin of the controller, which is about 3V, the sp3232 convert the 3v to about 5v output.