Hi Ray & All,

I identified a faulty serial cable. This is even more embarrassing as I had soldered the cable myself so many years ago following instruction from a brand new  computer book (at the time) and I was so proud of the accomplishment.

Once the cable was replaced with several other any large combination of serial extensions, USB cables, extensions, hubs worked fine. In the end it worked with 2 serial cable extensions of about 12ft each, 2 USB extensions of 6ft and 8ft and an unpowered hub in the middle. That's about the robustness I expect from simple wired serial protocol. (alas USB is pretty basic serial as well)

Ray, if I may ask you one favor. With all the extensions in place I recorded one last log from the driver.
http://skywatcher.space/download/AscomZip-Gert-2020-09-27-212330.zip

Could you please check it if there is any sign of data weakness? :-)

Cheers,
Gert