Some customers have complained about voice quality issues on the CP-500 phones, especially low volume through the handset. The following procedure describes how to modify this by increasing the default gain of the device.
IMPORTANT: This procedure could be used to change other default configuration parameters on the phone, but this is emphatically discouraged AND NOT SUPPORTED BY TAC.
Procedure:
1) Using notepad, create a file called "cp-524G-cfg.xml" with the following content:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<flat-profile xmlns="http://www.sipura.net/xsd/CP524SG" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sipura.net/xsd/CP524SG http://www.sipura.net/xsd/CP524SG/CP524SG-8-1-16.xsd">
<!-- Audio Input Gain (dB) -->
<Handset_Input_Gain ua="na">6</Handset_Input_Gain> <!-- options: -6/0/6 -->
</flat-profile>
In the above example, the new dB gain is +6dB (which might be too loud). We recommend that you start with 3 dB.
2) Put this file on the UC500 flash, specifically the "phone/521_524" directory, where the phone load is stored.
3) Create a TFTP Server entry via CLI, to instruct IOS to serve this file (use verbatim syntax, as shown below):
tftp-server flash:phones/521_524/CP-524G-cfg.xml alias /CP-524G-cfg.xml
4) Reboot your phone. If you have "debug tftp events" enabled, you can monitor the TFTP server activity (some output omitted below):
Jun 10 23:59:47.238: TFTP: Looking for /CP-524G-cfg.xml
Jun 10 23:59:47.282: TFTP: Opened flash:phones/521_524/CP-524G-cfg.xml, fd 11, size 416 for process 280
Jun 10 23:59:47.346: TFTP: Finished flash:phones/521_524/CP-524G-cfg.xml, time 00:00:00 for process 280
5) Check the new settings by opening a browser and point it to the phone IP. Look under the phone menu and check "Handset Input Gain":
You can also verify the new settings by pointing your broswer to the following URL, in order to see the raw XML configuration:
