I have an XML corporate directory that our company created internally to list all of our extensions. It works with the Cisco SPA phones, and also, with some modification, both Cisco 7900 series phones and yealink T4xS phones.
We have bought some Cisco 8800 series phones to evaluate. Cisco’s own documentation says that the option is supported in the 8800 series as well as the 7900 series phones and the SPA phones (Table 7 in the link below)
I haven’t found the example config yet for the 8800 series phones with that option in it. It seems like it’s not the same as the 7900 series phones, because I tried the 7900 config in the 8800 series phones and it seems to ignore it.
To expand your options, remember that chan-sccp-b (on GitHub) supports the 8800 series phones as well as the rest of the Cisco line. Not a recommendation (it’s a little daunting sometimes) but it’s a suggestion.
It maps the directory button on my Cisco 8841 to our internal XML directory. Below is just the part out of the wiki that does the directory button. The wiki entry also maps other keys which seem to work, although I am still testing.
<phoneServices>
<phoneService type="1" category="0">
<name>Contacts</name>
<!-- set the URL below to match your server DNS name, and edit the extension to match the correct extension for this file -->
<url> http://IP_Address/phonebook/79xx/pbmenu79xx.xml</url>
<vendor></vendor>
<version></version>
</phoneService>
</phoneServices>