Questions about RS-232 control of NexStar scopes are answered on the PC Control page. On that page I also include information and diagrams of the Hand Control RS-232 Port Cable and the PC Port Cable.
Currently it is possible to upgrade the firmware (software) for most models. See the "how to upgrade" articles on the Odds and Ends page for your particular scope. Also visit the Firmware Versions page for scope to see if a newer version is available.