USB-to-serial converters that work (especially with ILEC SN10) ?

Wow, can't believe all the problems with the new stuff that I know
nothing about. Thanks for confirming my decision to stay with my
prehistoric lap-top, prehistoric B-100 and prehistoric model-20 GPS
with Cambridge's prehistoric DOS software. Everything works and I got
all my soaring sites loaded in the B-100, even though I had to do it
manually. Dave tried to show me how to do it with one of them serial
ports, but lost me in a heart beat.

I do have a bit of a problem with the B-100 audio, it only comes on
when going fast, 70+ but no tone at thermal speed. Any suggestions? Not
a big deal because I use the audio on the B-40, like it much better,
because I can turn off the down (no bad news) audio.
Cheers,
JJ