Use the attached templates to build configuration files for your SPA3xx, SPA50xG, and SPA525G IP phones.
The SPA3xx and SPA50xG phones share the same SPC template
The SPA525G phone has a unique template [do not use SPA3xx / SPA50xG SPC output on a SPA525G. [even though the SPA3xx / SPA50xG SPC header shows SPA5x5.]
Each SPC template is unique to the version of firmware for which it was developed. Example, do not use revision 7.3.7 SPC output to configure a phone running revision 7.4.7 firmware.
Do not use SPA3xx / SPA50xG SPC output on a SPA525G. [even though the SPA3xx / SPA50xG SPC header shows SPA5x5.]
The SPC Utility provides the XML template for provisioning the SPA IP phones.
Download the SPC for the appropriate phone model and firmware version from Cisco.com, uncompress the file and run it in a Command Prompt [DOS prompt] without options for help. The utility runs on either Windows or Linux and supports either SIP or SPCP mode.
Make a new empty file and add to it, relevant lines from the SPC template. This is a line-by-line manual once-off task that you need to perform in order to configure your phones exactly as you want them. Less is more, so don't use the entire SPC template file unless you really need to change every phone parameter. You only need to include parameters that you want to change from factory default. If you don't specify a parameter, then the phone will keep the parameter as-is. Review the "Building the spa$MAC.xml Files" section starting page 10 of https://supportforums.cisco.com/docs/DOC-9954 for an overview of how to use the SPC tool and build a phone configuration file. [This is an Asterisk document, but the section in relevant to what you're needing in order to better understand using the SPC utility]
Attached are the resulting SIP-mode [for SIP call control] templates for your convenience.