Need to access old hardware or hardware that only comes with a serial interface? Well, there is an adapter for that. Only problem: Getting mac drivers for OS X Lion.
Turned out that this is not such a big problem, at least not if your adapter is running on the Prolific Chipset.
Make sure your adapter is connected to a USB port and open up
System Information. Select
Hardware -> USB and look for a
USB Serial Controller. When selecting it, you should get detailed information on that device. Does it look something like this?
If yes, you can consider yourself lucky. A guy called ./martijn wrote a driver that works under 10.7 and another guy called changux wrote a convenient installer for that same driver.