D-Link Xtreme N Duo DAP-1522 User Manual page 51

Section  - Configuration
Select PIN to connect your wireless device with WPS.
For PBC configuration, skip to page 52.
Enter the PIN number used into you access point and
click Connect.
Start WPS on the wireless device you are adding to you
wireless network to complete the setup.
D-Link DAP-15 User Manual 51