So don't we (to use Jaclaz' famous words: "I have my crystal ball at the shop for a retune") First make sure you've got a properly working TTL-RS232 connection before doing anything else. Install the interface's (USB) drivers. Check that a loopback-test can be performed at (at least) 38400 baud (Remember that not all CA-42 adapters are created equal; see other posts in this thread) Once you've got that working, come back here and describe exactly what you've tried and done. Like most (if not all) USB-devices, you first have to install the drivers before you plug it in. (Though Windows *should* respond and detect an "Unknown Device" once you've attached it) Possibility 2: You *could* have received a DOA (Dead On Arrival), if so return the interface for a replacement. Greetz, Peter. Hi, I can communicate with the drive, so I think the connection is correct, I can enter commands into hyperterminal ok unitl it comes to switching off the power at the HDD, once I connect it again I cannot enter anything into hyperterminal,(i've tried ctrl-z) the only way I can do that is by disconnecting the HDD power source again, but when I do that I can enter commands again but the process has been interupted and won't work The CA-42 cable is connected to a laptop via a USB connection, I have got a connection on all the three prongs that are used on the HDD (gnd, tx,rx) and I am using a external power supply like the picture in videoripper's post. I don't know what else I can try. Regards Ian