Dialing Plans are somewhat different from Signaling Network Plans. Dialing plans within a calling area are determined by the Public Utilities Commission (PUC) in each state.

Signaling plans are determined by the individual CLEC. Signaling changes may be required as a result of state-ordered dialing plan changes, and thus, may need coordination between CLECs. Again, timing and coordination activities would reference the Central Office Code (NXX) Assignment Guidelines.

An example of some possible dialing plans is shown below.

Minneapolis, MN	Seattle, WA	Denver, CO
• Multiple NPAs in the Minneapolis Metropolitan Statistical Area (MSA); NPAs are geographically assigned to a particular municipality and there may be multiple NPAs within a CenturyLink Rate Center.	• Multiple NPAs, not overlaid.	• Multiple NPAs; this is an overlay network.
• Commission ordered TN porting cannot occur between NPAs.	• Porting between the NPAs is not permitted.	• Porting between NPAs is permitted.
• If dialing outside of your own NPA, 10-digit dialing is mandatory but not necessarily a toll call.	• If dialing within your own NPA, 7 digit or 10-digit dialing is permissive. • If dialing outside of your own NPA, 10-digit dialing is mandatory but not necessarily a toll call.	• 10-digit local dialing is mandatory in all cases.