I am totally new to data comms and have loaded the current JT65 HF software and am using a USB driven interface cable from my Windows XP desktop PC to my old boat anchor Yaesu FT-902DM transceiver. the cable is from a UK company called radio Arena and is shown here (site can be slow): http://www.radioarena.co.uk/index.php?_a=viewProd&productId=2712 It has a LED on the case to show (I assume) when it triggers the PTT. Using the JT65 "Test PTT" button the LED on the interface lights and the PTT RCA plug that goes to the PTT connector on the back panel of the transceiver goes closed circuit, tested with a continuity meter. The rig however does not go into TX mode. Shorting the PTT connector terminals on the transceiver sends it into TX mode. Am I missing something like it also needs an audio signal input, or misunderstanding the "Test PTT" function in JT65? Or is it likely a hardware issue with the interface cable? Thanks!