Serial port issues on internal modem cards with Linux Kernel 3.8.x

PROBLEM: The newer Linux kernels >= 3.8 cause problems with serial ports on Multi-Tech's internal modem cards, such as corrupt data, missing ports, general serial control failures.

SOLUTION: Use Linux kernels prior to 3.8 (e.g. 2.6.x or instead until the kernel issues are resolved.

If running an LTS Ubuntu release (12.04), there is the option of running a few different kernel versions.

Here is a link to package names that reference LTS kernel back ports:§ion=all


If you are running Ubuntu 12.04 with kernel 3.8, then the linux-image-generic-lts-raring is installed, which is a back port of the kernel from Ubuntu raring to precise (12.04).  

You can remove the 3.8 kernel and install linux-image-generic-lts-quantal (3.5) using the software update, this way the kernel is changed without changing the Ubuntu release.