I'm trying to build a cable to use the Acc2 port to feed an external sound card and I have a few questions. I bought at usb sound card with 3.5mm plugs, I bought a 3.5 mm Aux cable to cut in half to be able feed both sides. If I'm doing it right Pin11 goes to the Mic side Pin 12 goes to the shield in that cable, Pin3 goes to the headphone side and Pin4 goes to the shield in that cable. My question is when soldering the wires to the pins there is a Red, White and Shield. Do you use just one of the red/white wire or do you use both. Also do I need to download anything on my Mac for the external sound card? Wsjtx recognizes that there is an external card and I select it and it shows around 35db on the meter but decodes nothing. If I play with starting to unplug the mic jack the db will jump up to 75db and it has decoded a few things. I'm trying to figure out why it isn't hearing good when plugged completely in.