Can someone tell me the difference between a multiplexor and the carsoft 7.4 black boxes sold on ebay for about $100? I contacted the companies that sell them on ebay in china, but i don't even think they know. The only thing i got out of them, was that their boxes have to be setup manually. But how do you set it up manually? I have an OBDII connector on my car, that plugs into the box, the box goes to the computer, what do you have to do manually? I just don't get it! Does anyone understand this?