You need WPS PIN to establish wireless connection. Are you wondering what is a WPS PIN for HP Envy 4520 printer? WPS or Wi-Fi Protected Setup PIN is an 8 digit code pin that is used to connect your wireless printer to your router or wireless network. To establish the connection, you need to first locate the WPS PIN on your printer. To find the pin on HP Envy 4520 printer, head to your printer Control Panel and launch the Settings. Then, click on the Wireless button and select for Wi-Fi Protected Setup. Follow the instructions on your screen and click on 'PIN.' The WPS PIN will appear on the screen now.