Alert info ringtone.

[Karl_Yealink]

4) Alert-Info: info=info text;x-line-id=0
When the Alert-Info header contains an info text, the IP phone will map the text with the Internal Ringer Text preconfigured (or the value of the parameter “distinctive_ring_tones.alert_info.X.text” is configured) on the IP phone, and then play the ring tone associated with the Internal Ringer Text (the ring tone can be configured by the parameter “distinctive_ring_tones.alert_info.X.ringer”). If no internal ringer text
maps, the IP phone will play the preconfigured local ring tone in about 10 seconds.

As the description above, you need to make sure the INVITE contain the Alert-Info: info=info text;x-line-id=0, so the phone will ring the ringtone what you want.

For the distincitive ringtone, you can get more info from the guide(page 740) below.
Link: http://support.yealink.com/attachmentDow...V80_95.pdf