The drivers for the Keyspan USB-Serial Adapter are in the mainline kernel (as of 2.6.x), as Keyspan notes. However, the drivers are (according to Keyspan) not in the Debian or Ubuntu kernels.
This is only partly true: Debian refused to use the Keyspan drivers due to their license; the fact that Keyspan drivers were missing from the latest Ubuntu kernels is a bug (#334285).
Since Linux Mint is based on Ubuntu, one can only hope that the kernel bug is fixed soon; I’d wanted to use my Keyspan driver with my laptop running Linux Mint 7.
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