The DZ68DB does not have a comport on the motherboard however you can install a third party com board. When selecting 115200 as the baud rate the display is mixed with garbage characters when sending and receiving. 9600 baud works fine. I've looked high and low for drivers or discussion on this subject to no avail. Has anyone experienced this or know a cause/fix?
That thread you linked to relates to a Linux installation but if you look on Intels list of supported OS's, your board (along with almost all other recent boards on the list) is not listed as having support for Linux. What OS are you using and what company is the manufacturer of the Serial Adapter board? I know you're probably keen to use one of your 3 PCI slots but as a simpler workaround, have you considered a USB to serial adapter?