You can guide three ways. ST4, PulseGuide or DirectGuide with a Paramount. In each case, you have to calibrate PHD2 using the same technique as guiding. Disconnect the ST4 cable, set up the ASCOM driver as in my earlier email and set up ‘ASCOM Telescope Driver for TheSky’. No need for an Aux connection. In PHD2, under the tools menu I think, you will find manual guide. You can move the mount, with guider commands. Set it to 5 seconds and you should see the mount location icon in TSX move. In fact, I would try this first, to prove that PHD2 is moving the mount, before trying to use SGP.