During a recent SRST event, internal DNs were unable to call each other. All other dialing (in and out over PRI) was working, but phones registered to the 2821 could not call each other ?! All DNs are three digits - 1xx. Received a fast-busy immediately upon dialing "1". No COR is being used anywhere.
Any ideas why the registered phones could not call each other?
Change that 'destination-pattern .' to 'destination-pattern .T' You never want to have 'destination-pattern .' for any scenarios where you have non-enbloc dialing.
'destination-pattern .' WILL get matched after the first digit and route the call. You can use 'debug voip ccapi inout' to observe this. By adding the T, it says that even though 'destination-pattern .' is a match, wait 10 seconds for other digits before committing to the dial-peer match decision.
Like I mentioned in a previous post, this is yet another reason why people use a trunk access code of 9 to dial PSTN calls. Then you don't have POTS and DN extension overlap. If you understand dialplan design well, you can get by without a trunk access code, but in my expeience most people that implement a dialplan without trunk access codes cause unwanted overlap and end up causing call loops, sending calls in the wrong directions, etc.