I have an Hw540 and an HW 720. The QD on each is different with the 720 plugging into a DA90 for USB access. The difference in the QD is the number of contacts, 4 in 540 and 6 in the 720. This makes accessories such as a POLARIS or A10 cable not work with the 720. Any enlightenment on how to order a complete set would be wonderful. By the same token, I cannot take my HW540 and plug into DA90 to use with USB,
