# Modify NPA/NXX Tables

To make changes to the NPA (area code) and NXX (3-digit prefix) tables.

1. From the Main Menu, select (S) System Maintenance, (R) Reconfiguration, (M) Restriction COS, (M) Modify selected RCOS, and then (T) Modify NPA/NXX Table.

2. Select (P) Select NPA and enter the number of the NPA to add.

   - If you are creating the NPA, select (A) Add NPA.

   - If you are deleting the NPA, select (R) Remove NPA.

   - The system confirms the modification.

3. To create/modify an associated NXX table, if necessary, select (N) Add NXX and enter the n umber(s) of prefix(es) to be added. NXX numbers can be entered in the following formats:

   - A single pattern, for example 252

   - A series of patterns, for example 252,428,354. Do not enter spaces after commas and do not end the entry with a comma.

4. To remove prefixes that you no longer need screened, select (D) Remove NXX and enter the number(s) of prefix(es) to be removed.

5. Select (B) Set NXX Screening to Allow/Disallow and A for Allow, or D for disallow.

6. To verify your changes, select (S) Show Table. The system displays your table and options.

7. To add another NPA, repeat this process starting from step 2.

8. Exit the RCOS Menu to save your changes.