I currently have 2 PBX at separate locations. They are connected via JSIP trunks and everything works fine. We have now the need to have the subset of extensions 6XX (Trunk1) access a specific voicemail at extension 503 (Trunk2)
When I do *98 and it asks to enter the PIN it responds with Login Incorrect. But the internal extensions (6XX) allow me to login with the same PIN successfully.
I guess this is related to the PBX’s being on different IP’s, even though they they are correctly done via the sip_nat.conf file and under the SIP settings.
I could be wrong but I think what you’re missing is that *98 is a feature code on the local PBX. That dial string is not contacting the remote PBX. The local PBX has no way of accessing the VM program on the remote PBX.
The way I work around this with my company over our inter-location PJSIP trunks is by using a “prefix” in the outbound route.
So, correlating my set-up to your system, you have PBX-5 with 5XX extensions and PBX-6 with 6XX extensions. In the outbound route on PBX-6 I have a pattern match of " 5XX " for extension-to-extension calling. But I also have a line with a prefix of “5” and a pattern match of " *985XX. " That way PBX-6 sees that dial pattern and knows it needs to be pushed over the trunk.