Hi Sandeep,
Customized Ring Tones
Cisco Unified IP Phones have two default ring types: Chirp1 and Chirp2. Cisco Unified CME also supports custom ring tones using pulse code modulation (PCM) files. An XML file called RingList.xml specifies the ring tone options available for the default ring on an IP phone registered to Cisco Unified CME. An XML file called DistinctiveRingList.xml specifies the ring tones available on each individual line appearance on an IP phone registered to Cisco Unified CME.
SUMMARY STEPS
1. Create a PCM file for each custom ring tone.
2. Edit the RingList.xml and DistinctiveRingList.xml files using an ASCII editor.
3. Copy the PCM and XML files to system Flash on the Cisco Unified CME router.
4. Use the tftp-server command to enable access to the files.
5. Reboot the IP phones.
Here are the details;
http://www.cisco.com/en/US/products/sw/voicesw/ps4625/products_configuration_guide_chapter09186a00806a8318.html#wp1155068
Hope this helps!
Rob
