We have freepbx 2.10 with asterisk 1.8 on IBM X3250 with 50 extension on yealink t20 range from 500 to 549. Users often make call forward on phone activating and deactivating, they are not using feature on PBX with *72. Problem is when do forwarding on phone in diversion part we have “Diversion: sip:[email protected];reason=unconditional” Is there any way to make or modify to have like “Diversion: sip:[email protected];reason=unconditional”? I manage to create extension with full e.164 number format (4333800500) instead 500 and add sip alias 500 so they can make call over short 3 digit number, but that is not happy solution. Sip provider require correct diversion header number format. I search for solution on google but not success. If anyone has a point to solution or link I would be grateful.
Part of log message from sip provider: