I am trying to explore FLDIGI using a TM-D710GA. I have the PG-5H cable kit but I'm confused about the connections for it. One of the cables is intended to connect the RX/TX unit of the radio to the PC's sound card. The other cable is shown to connect the RX/TX unit to a serial port on the PC - according to the printed manual that came with the radio. What is confusing is that the manual on the CD that came with the radio says (under the PACKET communication section) "The COM terminal is on the rear of the OPERATION PANEL. Connect this terminal to a personal computer: do not connect a computer to the PC terminal of the TX/RX unit. BTW - because none of my laptops has as serial port, I have a USB - Serial adapter (FT232R USB UART). I have successfully used the MCP-6A program to upload / download programming from the radio WHILE CONNECTED TO THE PC PORT ON THE BACK OF THE RX/TX UNIT. So, my questions are: a) Which is the proper connection point for the data (PC) cable to the radio when doing digital mode comms - the port on the back of the display (operation panel) - or is it to the port on the RX/TX unit? b) If the radio has a built-in Terminal Node Controller - why are the audio signal cables even needed. Wouldn't the TNC allow the radio to communicate to the PC via DATA signal? c) I noticed while experimenting with the FLDIGI program that I am seeing data stream on the incoming data window, and activity on the waterfall - even when there is NO possible source?! I have seen this when the radio is completely disconnected from the PC. I even disabled my network connection. How is this possible? Complete newb to this digital comm thing and will welcome any help I can get.