I have a lovely Wouxun KG-UV950PL 6/4/2/70 mobile radio, but a hands free kit doesn’t seem to be available. So I set about working out the connections required to build one. Here they are:
Using a standard RJ45 Ethernet cable:
- Orange+white / pin 1: RX audio – NC for this application
- Orange / pin 2: +5V on receive (unverified) – NC for this application
- Green+white / pin 3: PTT – wire to one side of switch
- Blue / pin 4: unknown, probably buttons – NC for this application
- Blue+white / pin 5: unknown, probably buttons – NC for this application
- Green / pin 6: +8V constant – wire to 2.2k resistor, then to positive side of mic
- Brown+white / pin 7: ground – wire to ground side of mic and to other side of PTT switch
- Brown / pin 8: – TX audio – wire to negative side of 100μF capacitor, then positive side of the cap to positive side of mic
Looking forward to building a version for the car and seeing how it is for road noise etc.
According to this, increase resistor size to increase mic output level (sounds counter-intuitive, but hey).
Update: that 2.2k resistor should be a 47k. That seems to produce clean audio and keeps the current through the mic element down. I’ve ordered a MAX9812 module to see whether a pre-amp brings the punchiness of the audio up a bit, since it’s a bit quiet as-is.