It is very possible you simply have NOT enough voltage. These thingy usually need something MORE than 3 V and up to 5 V. See here: http://www.msfn.org/board/index.php?showto...807&st=1592 http://www.msfn.org/board/index.php?showto...807&st=1594 jaclaz So I've switched to 5v from a USB port. Now the red rx light is pinned on, and tx flashes when I type a command. I'm unclear what a loopb ack test is supposed to do. When I connect the tx to rx on the adaptor, type something, the lights flash. Am I supposed to get a duplicate character back? i.e. if I type 'x' should I get a second 'x' back, displaying 'xx' on the screen? Tried seaching, but couldnt find specifics, only references.