Digit Manipulation for the Cisco CallManager
You can only apply digit manipulation to route patterns for outbound
calls only. This is because the digits need to be sent to the route list plus
the route groups. Individual route groups can have specific digit
changes for the same route pattern. You usually see this where a dialed
number needs to have different modifications like when devices need to
dial seven digits to reach a remote office that has a four digit internal
dial plan. This often happens when you have a call that cannot be completed
through the WAN and needs to be routed though the PSTN. What
would occur is the Cisco CallManager would prepend the first three
digits onto the dial string. A route pattern can be associated with only
one route list.