The wire for connecting balanced mics is the cc-1-xlr-y-bal, the one with the orange sleeve. I use this wire with a PR781 and a 6300 Foster socket. Notice the y in the model number, for Yaesu. Also note that the hand mic that comes with the radio is a Yaesu. If the PR40 has the same XLR pin-out as the PR781, then I think the orange sleeve wire is the right one. Take a close look at the wires sold on the FRS and Heil Sound websites.