[rocky2]

Prolific (Taiwan) provides drivers (ProlificUSBSerial1.0.6.pkg) for OS X for USB-Serial cables using their chipset but I cannot get the damned things to work under 10.2.6.
Have anybody had any success with these drivers at all or are they broken? I have searched the web for days reading about fixes like changing permissions and vendor and product IDs in the info.plist files but nothing does the trick.
Any solution except to badger Apple to provide some decent USB-Serial drivers in Panther?

[rocky2]

To post the answer to my question (courtesy of iDC at OSX Hints)

Install the Prolific 1.0.7b4 drivers.
Log in as root and use Text Edit to open the Info.plist in the ProlificUsbSerial.kext in the path
System/Library/Extensions.
In the Info.plist find the line
<key>IOKitPersonalities</key>
<dict>

and paste in the following after the <dict> tag:

--------Start paste

<key>5003_056E</key>
<dict>
<key>CFBundleIdentifier</key>
<string>com.prolific.driver.PL2303</string>
<key>IOClass</key>
<string>com_prolific_driver_PL2303</string>
<key>IOProviderClass</key>
<string>IOUSBInterface</string>
<key>bConfigurationValue</key>
<integer>1</integer>
<key>bInterfaceNumber</key>
<integer>0</integer>
<key>idProduct</key>
<integer>20483</integer>
<key>idVendor</key>
<integer>1390</integer>
--------End paste

Save the change and reboot with the UC-SGT plugged into the keyboard, etc.
The message that a new usbserial device has been found should be displayed.

That's it.