It isn't possible to connect by cable directly to the mount. A cabled connection must be made through the handset.
It is possible to do firmware updates via WiFi connection from the mount to a computer, using Celestron's firmware update program, CFM. See
https://www.nexstarsite.com/OddsNEnd...gradeHowTo.htm
Apparently Celestron's remote control program (CPWI) also connects via Wi-Fi, but I haven't used it yet. See
https://nexstarsite.com/PCControl/CPWI.htm
Michael Swanson's website, as referenced above, has a huge amount of useful information about these telescopes.
Regards, Andrew