If you looking SIP based services, here the example :
The 79XX phones have four panel keys labeled as Messages, Services, Directories, and Settings.
The Directory key can be programmed to view your company’s telephone directory by displaying Names and Telephone Numbers that are stored on any web site available to you.
Modify the SIPDefault.cnf file entry to point to the web site:
directory_url: “http://balajibandi.com/asterisk/directory.xml”
The phone must be rebooted in order to read the above file.
The web site file /asterisk/directory.xml should include xml entries like:
<CiscoIPPhoneDirectory>
<Title>IP Telephony Directory</Title>
<Prompt>People reachable via VoIP</Prompt>
<DirectoryEntry>
<Name>balaji</Name>
<Telephone>9999</Telephone>
</DirectoryEntry>
<DirectoryEntry>
<Name>bandi</Name>
<Telephone>9992</Telephone>
</DirectoryEntry>
</CiscoIPPhoneDirectory>
Note: Each time a user presses the Directory key and accesses the External Directory option from the menu, the phone will access the contents of this html file and display whatever text entries included in it. Therefore, changes to the html file do not require any futher rebooting of the Cisco phone. Cisco has published Cisco IP Phone Services Application Development Notes (CMXML_App_Guide.pdf ) that further explains options and file contents.
