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It is actually pretty clearly spelled out in the user documenation on unifiedcommunicatorexpress.com, look here: http://download.unifiedcommunicatorexpress.com/ucx/3.2/UCExpress_3.2_Users_Guide.pdf starting on page 51 or so...
Why do you need to know about this, what issue are you having, normally you would just create rules and set up windows dialling locations, you dont need to do anything in the number parsing field.