The AOSS button is located on the wifi router, not the PlayStation Portable. AirStation One-Touch Secure System (AOSS) is a system that enables a network connection to be created with a single button press. Please consult the manufacturer of your router for additional information.
Sometimes, a router with a WPS button will also establish an AOSS connection. If an Internet connection – AOSS error warning displays on your PlayStation Portable, navigate to Wi-Fi Settings under Network and retry AOSS before restarting the application and system. If the fault persists, contact the manufacturer of your router.