This is a bit of a success story.

After trying no less than six different USB 2.0 to Serial adaptors trying to
download a flight from a Volkslogger with SeeYou, StrePla and DOS, I finally
bought a $75 high-speed serial PCIe card. Using this card, SeeYou
downloaded a secure file from the Volkslogger in about 20 seconds. OLC
accepted the file from SeeYou just as quickly - no red mark.

The USB adaptors seemed to work and would download a non-secure file but the
secure file was always corrupted. USB 2 adaptors may be the source of some
of the problems.

Bill Daniels