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Thread: Oxy mask connection

  1. #1

    Join Date
    Nov 2011
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    Hood River, OR
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    32

    Goggles Oxy mask connection

    When connecting the oxygen mask microphone U173/U to the microphone cord with a U172/U connector, are these pins polarized or can they be plugged in either way? It is just grounding the mic. wires. I can't see how they could be polarized. However in some airplanes when I plug into the airplane all is good and on some airplanes when I plug into the airplane squealing results. Me or airplane?? Am I looking at the wrong thing? Could it be airplane wiring?

  2. #2
    rwanttaja's Avatar
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    Jul 2011
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    Seattle
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    2,963
    Seems like if polarity was important, they would have designed the individual posts differently. In this shot, they look identical
    Name:  u173u.jpg
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    Oddly, on another shot I took, the posts are actually different...but STILL not different enough for a polarization guide.
    Name:  u172_2.jpg
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    If you can, in the squealing cases disconnect the U173 and turn it the other way.

    Ron Wanttaja

  3. #3
    Dana's Avatar
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    Jul 2011
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    942
    If it's an old fashioned carbon or dynamic microphone, polarity shouldn't matter. If it's a modern electret mike, polarity will matter.

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