I operate an orange C14 with G-11, autoguider and PHD2. The essential? remarks were already made. Still some comments.
For several years I used on-line guiding, because it worked and I did not want to experiment with software and special cables. However the guider needed two cables: one to the PC and one to the mount port. A C14 is big, and guarding the wires at night is a hassle. Every wire less is much better. Then it appeared that switching to direct PC guiding could be done by trhree mouse clicks. One wire less. All going through ASCOM. PHD2 knows were the mount is, so less PHD2 training. I think the guiding ports on ZWO and G-11 have no function anymore.
I have an older (2007) Gemini system running a G-11 mount. I have recently purchased a ZWO ASI120MC-P which I intend using primarily as an autoguider.
What I need to know is what I should connect the ZWO guider port to so the PHD2 can find it and control the Gemini-1? Obviously, direct connection of the ZWO to the Autoguider port on the Gemini-1 cannot be seen by PHD2 - there has to be some RJ-11-to-RS232-to-RJ11 guider port arrangement.
I suspect this is common knowledge to many, but as the technology is getting on a bit, it's seems to be getting harder to find. I've been advised by Brian at Losmandy support that ST4 pulse guiding would probably be best for my situation. What can anyone suggest?