Sony SRS-XB21 Help Manual page 18

The speaker is initialized.
All pairing information will be deleted. If you initialize the speaker, it may not be able to connect your iPhone/iPod touch or
computer. In this case, erase the pairing information of the speaker on your iPhone/iPod touch or computer, and then perform
the pairing procedure again.
The speaker can be paired with multiple devices, but can only play music from one paired device at a time.
When an audio cable is connected to the speaker's AUDIO IN jack while the speaker and the BLUETOOTH device have been
connected via BLUETOOTH connection, sound from the BLUETOOTH-connected device is not output from the speaker (the
hands-free function is available). To listen to music from the BLUETOOTH device, disconnect the audio cable from the speaker's
AUDIO IN jack.
Related Topic
Listening to music of a device via BLUETOOTH connection
Terminating the BLUETOOTH connection (After use)
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