Sony MDR-AS700BT - Manual (Page 40)

Note
If pairing is not established within about 5 minutes, pairing mode will be
cancelled and the headset will turn off. In this case, start over from step 1.
2. Select the BLUETOOTH setting on the smartphone.
Select [Settings] [Bluetooth].
3. Turn on the BLUETOOTH function on the smartphone.
Touch the button next to [Bluetooth] to turn on [Bluetooth].
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