Called and Calling Parties Transformation Priority For Outgoing Calls

Digits manipulation on Cisco CUCM is the most important part of the Dial Plan. To understand this concept we need to split it into two parts:

-Digits Manipulation for Outgoing Calls
-Digits Manipulation for Incoming Calls

For outgoing calls we can perform digit maniplation at different levels, From the route pattern level, route group at the route list details level, at the gateway or sip trunk via the outbound calls section, translation pattern before making a decision of call routing through a route pattern, or transformation pattern associated to the gateway or sip trunk using a partition and CSS applied after a route pattern. This flexibility gives us a granular choice to select the best level of manipulation.

Now what if we have multiple digits manipulation at different levels for outgoing calls. Cisco CUCM will apply a preference based on the following logic to extend a call.