The ExploreStars app only works wirelessly. The PMC-Eight ASCOM Driver can be used either wired or wirelessly. The ExploreStars application is designed to be used as the primary hand controller for the PMC-Eight system. You cannot connect and run the ExploreStars application via the serial/wired communications channel in the PMC-Eight.
If you want to connect the computer via a serial cable of the following types:
Mount Cable Type
G11/EXOS2 USB to Male DB9 Serial adapter cable (FTDI chipset)
iEXOS 100 USB Type A to mini-USB Type B
You would need to use the ASCOM driver with an appropriate ASCOM Client program.