Telephone numbering data comprising an NPA code associated with an NXX code that is associated with a rate center identifier is received at a dial plan instruction writer. Local call data relative to a home rate center is also received. The local call data determine whether a call originating in the home rate center is charged as a local call, a toll call, or a long distance call. Routing rules to be applied to a called telephone number originating from the home rate center are determined based on the telephone numbering data and the local call data. Instructions executable by the telephone switch that implement the routing rules are generated.