I guest to measure the slicon omni mic this day, we have compare two pieces of them. The one piece is good and the other one is unuseless. You only need Ohm meter to measure this part as well. Ok look at the picture below


I call bellow part for GND, center part for IN and top part for OUT. Just put yor black probe to GND and red to another one. This size not compromise by Nokia, its only our job and maybe vary various size limit.

Normally
GND to IN approx to 4.xxMohm
GND to OUT approx to 2.xxMohm

Noisy
GND to IN approx to 2.xxMohm
GND to OUT approx to 1Mohm and bellow

Bad or malfunction
GND to IN approx to 0 ohm
GND to OUT approx to 2.xxMohm