When your headset is correctly plugged and recognized by your device, an icon is displayed in your status bar.
If this icon is not displayed, it's possible that your headset doesn't use the right standard. A microphone headset is composed of 3 crowns, including a section dedicated to the mic. There are two different valid standards: CTIA and OMTP. If your headset is set with the CTIA format, it is not compatible with a device that requires a OMTP headset (and vice versa).
The only solution is then to get an adaptator that will change the standard of your headset. We recommend you to use the headset provided with your device, if availabble, or to get a compatible headset available on our online store.
If you have Bluetooth® on your device, you can also use a Bluetooth® headset, compatible A2DP. This process lets your device manage your calls.