External Interface Jack Pinout ------------------------------ Pinout for the 10-pin round interface jack on the bottom of the Mitsubishi-900: (the SMA jack in the center of the circle is for an external antenna and/or booster kit.) Starting at the "1:00" position and continuing clockwise around the circumference of the jack, pin 1 - LCURUN (inverted) pin 2 - HFE (HFON) hands-free ON (?) pin 3 - DS1D (inverted) pin 4 - EXT-ON external ON (?) pin 5 - DS0D (inverted) pin 6 - TXPS pin 7 - RAUD receive audio pin 8 - MCHG (STPB inverted) pin 9 - GND ground pin 10 - TAUD transmit audio -end