The last piece of the puzzle configuring routes. This is pretty easy if you are used to the power of .net regular expressions but if your not it can be quite a step learning curve. Lucky MSFT have provided a good tool with the route helper tool. This will help you fault find problems with your expressions and will provide assistance writing them.
In the example, things are pretty simple with some more specific routing for the some local Washington area codes. Now you may have noticed some repeated number patterns in there that accompany alternate routing provide through the order of phone usages. Of course, these repeated number patterns route to different mediation servers. Some may have noticed that the 911 pattern seems a little strange as well. This is because where I work we are sending the EPID attached to the number pattern to our 911 provider gateway to work with our location management system to provide E911.
Anyway, I will let the picture paint the rest of the story. I hope showing the different segments in this diagram fashion has helped improve your understanding of OCS dial plans. Next week I am going to be doing a similar thing with response groups and showing how the different response groups look when in diagram format.