RE: Inspiron 17 5748 does not recognize external microphone
That suggestion was incorrect, because the Windows native driver doers not support the external mic jack.
Now that I think about it again, the Windows native driver in Windows versions prior to Win10 did not support the jack. Win10 changed the way Windows handles the audio, and might have included that feature in the Win10 native audio driver. I don't have Win10 so cannot test it one way or the other, so it might be a while before I am able to find out.