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Increasing the Handset Volume of a CP-500 Cisco IP Phone


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.


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="" xmlns:xsi="" xsi:schemaLocation="">
<!-- Audio Input Gain (dB) -->
<Handset_Input_Gain ua="na">6</Handset_Input_Gain> <!-- options: -6/0/6 -->

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":

Picture 1.png

You can also verify the new settings by pointing your broswer to the following URL, in order to see the raw XML configuration:



Just to be sure of it, does this procedure work for the CP-521 as well?


Yes it should.



On the thread which generated this document, you said that you were working on a procedure to change the configurations of all phones at once (which you did). Is there a mechanism to change the gain on only some phones?  And if so, does that mechanism peacefully co-exist with this method, or are they mutually exclusive?




You can create XML files per phone (using their MAC address). Do a debug TFTP events while you restart the phones and you will see how you will have to format the file name.




I'm having trouble following your directions Marcos.  I started a discussion about it to save cluttering up the comments here.


I've been having a nice conversation with myself as I follow this through.  It's come down to this now though: exhaustive analysis of debug tftp events has NOT suggested any way to to configure the handset gain on a per-phone basis.



Is there a way to change the input gain for Cisco 7910 IP phones ?

Can the XML configuration for the phone be obtained via the web URL ?