Serial-to-USB cables allow connecting RS232-based devices to computers that only have USB ports. Most serial-to-USB cables, including those from BAFO and IOGear, feature Taiwan-based Prolific Tech’s PL2303 chip.
This chip comes with drivers for Windows and [[Mac OS X]]?. Linux has it built in. The Mac driver has for long had a bug that affected GPSBabel, resulting in mysterious “No DLE” errors when reading from Garmin devices. The bug has now been fixed, but may require some mucking around to get it to work.
Fixing PL2303’s Mac drivers
Download and install the driver, connect the device, and look for a /dev/cu.usbserial node. If it doesn’t exist, open System Profiler from /Applications/Utilities and look under USB devices for the device’s product and vendor id. Convert those numbers from hex to decimal (8200 and 1367 respectively for my IOGear device). Next, open /System/Library/Extensions/ProlificUsbSerial.kext/Contents/Info.plist and update the idProduct and idVendor keys under IOKitPersonalities/067B_2303. Finally, run these at the command line:
sudo kextunload -b com.prolific.driver.PL2303 sudo kextload -b com.prolific.driver.PL2303
That should create a /dev/cu.usbserial node. GPSBabel will continue to have errors, but this matches the behaviour on other platforms. Rerunning GPSBabel 4-5 times results in a clean run, which, previously, was not possible at all.
Resources
- Prolific PL2303 driver download.
- IOGear’s adapter, which uses the Prolific chip.
- Keyspan’s adapter, which does not use the Prolific chip and apparently has good Mac drivers.
