Cisco 7925G Deployment Manual page 45

Use the short preamble setting in the 2.4 GHz radio configuration setting on the access point when no legacy clients that require
a long preamble are present in the wireless LAN. By using the short preamble instead of long preamble, the wireless network
performance is improved.
Enable WPA policy with TKIP in order to use CCKM, when 802.1x authentication is used.
The WMM policy can be set to "Required" if only the Cisco Unified Wireless IP Phone 7925G or other WMM enabled phones
will be using this SSID.
If 7920 or other non-WMM clients will associate using this SSID, then ensure the WMM policy is set to "Allowed".
Enable "7920 AP CAC" to advertise Qos Basic Service Set (QBSS) to the client.
Cisco Unified Wireless IP Phone 7925G Deployment Guide 45