You can configure the distinctive ring tones via the phone’s Web UI. 
Configuration as shown below: 
When receiving an INVITE Message with Alert-info (Alert-Info: <http://127.0.0.1>; info=internal), the phone 
will play the “Doing Doing” ringtone. 
 
7.4.1.1 Alert-Info: Bellcore-drN 
When the Alter-Info header contains the keyword “Bellcore-drN”, the IP phone will play the desired ring tone. 
The following table identifies the corresponding ring tone: