The Aastra phones support Bellcore distinctive ringing. On any freepbx configuration screen that has the “Alert Info” box you can enter the distinctive ring command:
<Bellcore-dr3>
the “3” can be any number between 1 and 4, each one giving a different distinctive ring.
The format is critical. You must use the Greater than and Less than signs, capitalization, etc. to make this work.
BF