TRRS wiring question

Wolfetone

I need to use my smartphone as a recorder and I want to use an external microphone. I have bought a TRRS adapter but the thing won't work. What connections do I put the multimeter on to show it's working or not?

I know that the long cable and the microphone works.

Danny1969

There's 2 ways the socket can  wired so you need to know which way yours is, see this pic :

As you can see the ground is moved and that stops one device being compatible with certain others unless you move it in a cable