Press and hold the POWER button for about 2 seconds.

Make sure that the indicator (blue) flashes after you release the button.

If the iPhone was connected with the headset the last time, an HFP/HSP connection is made when you turn on the headset.

While the headset is on, you can make an A2DP connection (music playback) by pressing the button.

Check the connecting status on the iPhone. If not connected, proceed to step 2.

Touch [Settings] [Bluetooth]. Make sure that [ON] is selected, then touch [MDR-10RBT].