PBX: Internal Grandstream UCM6104
Snom 760 Firmware: 18.104.22.168, 22.214.171.124
We have inbound routes configured on our PBX to prepend the Caller Name with a note which helps our team determine who is calling. This has worked flawlessly for years, until yesterday... Suddenly, all of our 760's running the firmware versions listed above stopped reporting the Caller Name provided by the PBX and instead started showing different names - like 'skype', 'Anthony' etc. I presume this is only happening when other SIP lines are calling.
I upgraded a couple of phones to the latest firmware available for these devices, which has resolved the issue for some of the calls - however, a lot of inbound calls are still showing custom Caller IDs instead of the Caller ID that the PBX is reporting and sending to the devices.
The PBX configuration hasn't changed, no configuration on the phones themselves was changed. We have Fanvil phones on-site as well, which aren't showing these issues at all (so far). Does anyone have any idea what could have happened here?
Thanks in advance for any help you might be able to provide :)
How is the information being altered by your Grandstream PBX (SIP INfFO, LDAP) and delivered to the Snom phones? It sounds like either the From, Contact or P-Asserted identity headers are not being overwritten by your PBX or delivered based on it's rules and the phone's are displaying the information based on the settings for displaying contact source priority.
This is purely speculation without seeing a SIP INVITE, the settings file and more information.