Blue wire is not needed w/Yaesu VX-6R. PTT and MIC audio share the White wire and requires the 2K Ohm resistor for PTT and 10uF Cap to audio line. Blue wire is actually connected to GND!
Pinouts For VX-6R:
Tip = Red -external Speaker
First collar = No connection
Second collar = White - Mic (and PTT w/2K resistor)
Sleeve w/threads = GNDRating: [5 of 5 Stars!]