I just tried it. You get what you pay for. I will use it for a couple of weeks and then send it back. $ 7.50 postage down the drain.
It was pretty easy to set up and the first couple of calls were amazingly clear. I was using a standard phone with no power supply. The Jack doesn't supply enough power to the phone to light the dial display.
The last couple of calls I made, I could hear my voice lagging behind my speaking voice in the phone. I changed to a phone that has a power supply and cordless. It does the same thing.
Two incoming calls were clear and one was very poor.
The computer I am using is a 1G machine. I ordered a 10 buck USB 2 card so the speed shouldn't be a problem. My Internet connection is Charter cable and I have a 5M/512k connection.
I do have a 3.2 machine, but I don't leave that machine on 24/7 so even if it worked better on that machine, I don't think I would keep it.