How do I use the HP Envy Photo 7800 without a wireless router (Wi-Fi Direct)?
Make sure Wi-Fi Direct is enabled by opening the Dashboard and touching the Wi-Fi icon to check its status, network name, and password. By default, Wi-Fi Direct is set to 'Automatic' mode, which allows anyone in wireless range to connect without a password. For higher security, HP recommends changing the connection method to 'Manual' and setting an administrator password through the printer's embedded web server (EWS). (Page 2)
From the official HP Envy Photo 7800 All-in-One Printer manual, page 2
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