What is the most effective method for testing roaming in relation to 802.11 VoIP handsets?

You are using a tool that allows you to see signal strength for all Aps in the area with a visual representation. It shows you SSIDs available and the security settings for each SSID. It allows you to filter by frequency band to see only 2.4 GHz networks or only 5 GHz networks. No additional features are available.
What kind of application is described?

When implementing PoE, what role is played by a switch?

What security solution is deprecated in the 802.11 standard and should never be used in any modern WLAN deployment?

During a post-implementation survey, you have detected a non-802.11 wireless device transmitting in the area used by handheld 802.11g scanners. What is the most important factor in determining the impact of this non-802.11 device?