CWNA

Answer - C - You should test the site for RF coverage with the 2.4 GHz phone on during a site survey.

Key Takeaway: Many cordless telephones use the 2.4 GHz frequency; the frequency at which Wi-Fi standards 802.11b, 802.11g, and 802.11n operate. This can cause a significant decrease in speed or sometimes the total blocking of the Wi-Fi signal when a conversation on the phone takes place. Some of the ways to avoid this is to use the Buy DECT 6.0, 1.9 GHz, 5.8 GHz or 900 MHz phones, use VoIP/WiFi phones, and test several different Wi-Fi channels to avoid the phone channels.