i have 2 pabx in different site s20 and the other s50
problem: unable to use PSTN trunk of s20 from extensions of s50 error Q.850 = cause 21 ,but s20 can use PSTN trunk of s50 from s20's extensions
i have 2 pabx in different site s20 and the other s50
problem: unable to use PSTN trunk of s20 from extensions of s50 error Q.850 = cause 21 ,but s20 can use PSTN trunk of s50 from s20's extensions
The cause code (21) is indicating a rejection. Without knowing more of how the rules are set it may be problematic to determine the reason. You have provided the result without any of the details of how the inbound and outbound routes are set between the two UCMs and if the remote extensions have the needed permissions to use the other sides' trunks.
Forgetting about the trunks for the moment, do we assume that each side can reach the other sides' extensions?