Wow, there is a lot of conflicting and confusing information in this thread. When it comes to connecting a SynScan mount to a computer, the information is confusing simply because there are many ways to accomplish the connection. Everyone gives you a tiny bit of information about how they connect without full context of everything required. So, everyone can be telling you how to connect but you cannot mix and match all the different partial advice you get to make it work.
Below is a chart I put together that shows all the different ways you can connect. You can choose any one method (shown as different rows) but you cannot mix up connection methods shown of multiple rows at once. This chart was made for the EQ6r_pro but is valid for the Sirius mount also. I think you have been trying to use method #2 in the chart where the USB goes from the computer to the Hand Control and then the Hand Control is plugged into its normal RJ45 connector on the mount. You can use any one of the software drivers in the rightmost column for a given row. Note that connection method #3 is very similar with the only difference being the Hand Control configuration and the device driver being used.
Do not mix up connection methods. (For example if you use #2, you must use either EQMOD or GSS and put the HC into PC-Direct mode. If you use #3, you must use the SW ASCOM driver and not put the HC in PC-Direct mode.) (Other combinations will fail when you use something from Row #2 versus something else from row #3.)
In addition, I wrote up a tutorial of the more common ways to reach a connection that works. However, the methods in the tutorial predate the inclusion of USB connectors on the mounts by SkyWatcher and Orion. As background, you can read through the tutorial and then use the chart above to choose one method to get a working connection.
PS: As @Tangent indicated above, when using a USB connection, you should make sure to download and install the Prolific Chipset Device Driver from the SkyWatcher website. This is required to use the USB ports on either the mount or Hand Control. (Some generic Prolific drivers automatically installed by Windows may or may not work properly. Skywatcher's website has a version that they have tested and is known to work.)
Edited by jdupton, 04 December 2022 - 10:47 AM.