Existing users, 
I have an older palm IIIxe. I use the USB to serial adapter with my G4 and OSX 10.3. What works for me is if I briefly unplug the USB cable coming from the adapter and then plug it back into my USB hub. Then press the hotsync button. This works for some reason.
The act of plugging in the USB most likely relaunches the palm driver so that it looks for the hotsync signal.
Unfortunately all the deleting and re-installing make no difference. This is the only work-around I have found that works.
Good luck!
Palm Desktop
for some Treo, Tungsten, Zire models
Version: 4.2.1revD
Hotsync Problems with USB-Serial
Feedback Type: Usage Tip
Contributed by: ctumpach Tuesday, February 03 2004 @ 09:53 PM PST
Product Platform: MacOS,MacOSX
Used Product For: Over One Year
Recommend Product: NO
Comments
Hotsync Problems with USB-Serial - elvinc_dotmac
I just got a PalmConnect USB for my IIIxe. I'm using it with a new dual 1.8 G5.I've found with experimenting with all USB ports I have...it only worked with the ports I have on my Apple Cinema. I can only theorize that because it acts like a hub, and has some other ports active (keyboard and mouse) that it somehow keeps traffic active so that the hotsync signal is heard.
But of course, it's not consistent. Today I tried all the same ports, even unplugging a mouse and quickly plugging in the cradle to sync. At best, I got a sync which stopped midway due to an error.
At this point, I'm ready to eBay a USB cradle native Palm to try and see if I can avoid this problem.
-elvin-
Wednesday, April 06 2005 @ 09:16 PM PDT
Hotsync Problems with USB-Serial - elvinc_dotmac
well with further testing. It appears that there needs to be some extra traffic on the hub besides the hotsync signal for the HotSync Monitor to pay attention.No kidding...if i wiggle the mouse (I figure keyboard strokes will do it too)...then press hotsync...ta-da! The hotsync is consistently heard and completes without error.
I doubt this will work on the isolated USB port that is not being shared by keyboard or mouse.
-elvin-
Thursday, April 07 2005 @ 04:01 PM PDT
Hotsync Problems with USB-Serial - Fotmasta
Same here, but with palm vx.Reply to This
Thursday, February 05 2004 @ 08:17 AM PST