Pioneer AVIC-S2 - Manual (Page 15)

1.7 Using a SD Card
NOTE: Make sure that no foreign objects enter the slot.
Your device features a SD slot where you can insert the Secure Digital storage
card used for map data, storing MP3 files on your own SD card, and future
software and application updates. To use a SD card, insert it into the slot, with
the connector pointing toward the slot and its label facing the front of the device.
To remove a card, first make sure that no application is accessing the card, and
then slightly push the top edge of the card to release it and then pull it out of the
slot.
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