I have a problem with 7925G IP phones. While performing site survey with 7921 and 7925G phones, i have noticed that voice quality is poor on 7925 while 7921 still working properly. I have WLC5508 and 4404 version 6 and 1121, 1131 and 1141 APs and I'am using 802.11b/g/n. TPC is set to the maximum "1" and DCA is fixed, WMM is set to Allowed, QOS to Silver. I have also noticed that tx power for 7921 is 17dBm and for 7925 it is 14dBm. I have tried upgrading 7925 firmeware to 1.3.4 which was 1.3.3, also tried change "Call power save mode" to none and still have the same problem.
I would like to know if there is a way to change tx power of the 7925 to its maximum which is 16dBm for OFDM and 17dBm for CCK.