For the impatient

The driver made it into the linux kernel!
Kernel 2.5.2 and later contain a working version. In the stable series you will find it in 2.4.18 and later. The last released version available from me is still here (0.3a). Sorry for the delay with a newer version -- I was too busy the last months, and have only received 5 reports of 'works' or 'has problems' from users out there. I hope to get the new version out Real Soon Now. If you are waiting for it, let me know! Check back here.
Send any comments you might have to haus@uuhaus.de.

Details

The PalmConnect USB Serial adpater is a simple 1-port USB->Serial adapter with a DB-9 'male' serial connector sold by Palm Inc. for use with their Palm V/Vx and older handheld PDAs.

Palm Inc. was not at all cooperative (i.e. did not truly respond besides 'please download the latest drivers' and 'yes, but we now even have Macintosh-drivers'-type messages) in getting a Linux driver developed. They contracted the work of writing the Windows drivers to MCCI who were kind enough to help me make contact with KLSI, the producers of the chip used. I finally received specs from them (without NDA or other hassle). Thanks!

Being tired of waiting, needing a solution quickly, and being stuck with this device I started implementing a rudimentary driver from what I learned by playing with ComTest, a tool to toggle serial line bits under Windows and sniffing the USB transactions (and the transactions happening during a real-life palm sync) using USB Snoopy and usbsnoop. That resulted in a driver that integrates into the Linux USB layer in the Linux kernel.
Now, reading the specs, it seems that the windows driver from Palm is rather cheaply done -- it never changed stop bits or byte size to 5 or 6, although the chip supports it. And isn't that one of the main features you look for in a serial device? :*)

Some firmware for KLSI's products incorporating the KL5KUSB105D chip (note that they use the ...D revision/version, while the PalmConnect seems to have a ...A revision/version; it seems that the ..D revision and the KL5KUSB116 chip use a newer protocol; I do not have specs or a device to look at for these) is available from them, along with drivers for windows and MacOS. If you want to have fun with disassembly: The chip is based on ScanLogic's SL11R chip, which has documentation readily available in their Developer's kit.

If you have any other information or even documentation, I would be most interested. A firmware dump of the palmconnect device, a sl11r disassembler (doing that by hand is not my favorite pastime) are other items that would be nice. If you know anybody inside one of the mentioned companies that could be of help, please help me make contact.

There seem to be more devices appearing on the market that use this chip (maybe it has become cheaper?). The product-ID used seems to get changed, usually, so if you are successful with the driver after changing the product ID, let me know so that I can list it in the driver.