Planning Letters
The Planning Letters (PL) and Informational Letters (IL) are sorted by publication date. To view or download a PL or IL, you can search by year or search by planning/informational letter number. To search by a planning letter number e.g., 623, select “Any” as the year and enter the Planning Letter number using this format “PL-XXX” e.g., PL-623. To search by an Informational Letter, select “Any” as the year and enter the Informational Letter number using this format “IL-XX-XX-XXX” or “IL-XXX-XX-XX-XXX” e.g., IL-91-05-035.
The PL page does default to “Any”
| Year | Number | Subject |
|---|---|---|
| IL-91-08-009 | NANP-REVISED NPA MAP SHOWING NEW NPAS SCHEDULED TO BE INTRODUCED IN 1992 AND 1993 |
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| IL-91-08-001 | NANP-INTRODUCTION OF THE 917 NUMBERING PLAN AREA (NPA) IN NEW YORK CITY AND TRANSFER OF THE BRONX, NEW YORK, FROM THE 212 NPA TO THE 718 NPA |
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| IL-91-06-044 | NANP - CORRECTIVE CONSIDERATIONS FOR ELIMINATION OF BLOCKED NETWORK CALLS FROM CERTAIN CUSTOMER PREMISES EQUIPMENT |
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| IL-91-05-035 | NANP - INTRODUCTION OF INTERCHANGEABLE CENTRAL OFFICE CODES IN THE TEXAS 713 NPA |
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| IL-91-05-028 | INTEGRATION OF PUBLIC NON-LEC ISDNS INTO THE NORTH AMERICAN NUMBERING PLAN |
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| IL-91-03-009 | NANP - INTRODUCTION OF INTERCHANGEABLE CENTRAL OFFICE CODES IN THE 714 NPA |
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| IL-91-02-030 | NANP - REVISED NPA MAP SHOWING NEW NPAS SCHEDULED TO BE INTRODUCED IN 1991 |
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| IL-91-01-045 | NANP - INTRODUCTION OF INTERCHANGEABLE CENTRAL OFFICE CODES IN THE 206 NPA |
| Year | Number | Subject |
|---|---|---|
| IL-90-12-050 | NANP - REMINDER OF FEBRUARY 1, 1991 DATE FOR ELIMINATION OF THE USE OF THE 706 AND 905 NPA CODES FOR CALLS TO MEXICO |
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| IL-90-12-049 | NANP - SPLIT OF THE 301 (MARYLAND) NUMBERING PLAN AREA (NPA) |
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| IL-90-08-055 | NANP - SPLIT OF 213 (CALIFORNIA) NUMBERING PLAN AREA |
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| IL-90-08-052 | NANP - REMINDER OF NUMBERING PLAN AREA (NPA) CODE SPLITS IN TEXAS AND NEW JERSEY |
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| IL-90-07-004 | NANP - INTRODUCTION OF INTERCHANGEABLE CENTRAL OFFICE CODES IN THE 215 NPA |
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| IL-90-06-023 | NANP - REVISED DATE FOR SPLIT OF 415 (CALIFORNIA) NUMBERING PLAN AREA |
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| IL-90-04-003 | NANP - INTRODUCTION OF DIALING PROCEDURE CHANGES IN THE 202 AND PORTIONS OF THE 301 AND 703 NUMBERING PLAN AREA (NPAS) |
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| IL-90-04-002 | NANP - INTRODUCTION OF INTERCHANGEABLE CENTRAL OFFICE CODES IN THE 205 NPA |
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| IL-90-04-001 | NANP - INTRODUCTION OF INTERCHANGEABLE CENTRAL OFFICE CODES IN THE 512 NPA |
| Year | Number | Subject |
|---|---|---|
| IL-89-12-022 | NANP - INTERCHANGEABLE CENTRAL OFFICE CODES IN THE MICHIGAN 313 NPA |
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| IL-89-10-072 | NANP - INTRODUCTION OF INTERCHANGEABLE CENTRAL OFFICE CODES IN THE 919 NPA |
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| IL-89-10-049 | NANP - REVISED NPA MAPS SHOWING NEW NPAS SCHEDULED TO BE INTRODUCED IN 1989 AND 1990 |
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| IL-89-10-048 | NANP - INTERCHANGEABLE CENTRAL OFFICE CODES IN THE TORONTO, ONTARIO, CANADA 416 NPA |
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| IL-89-10-047 | NANP - INTERCHANGEABLE CENTRAL OFFICE CODES IN THE ARIZONA 602 NPA |
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| IL-89-09-010 | NANP - SPLIT OF THE 201 NUMBERING PLAN AREA |
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| IL-89-05-038 | NANP - RELIEF OF THE 214 NUMBERING PLAN AREA |
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| IL-89-04-028 | 312 NUMBERING PLAN AREA (NPA) CODE SPLIT IN ILLINOIS |
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| IL-89-02-014 | NANP-INTERCHANGEABLE CENTRAL OFFICE CODES IN 404 NPA |
| Year | Number | Subject |
|---|---|---|
| IL-88-06-012 | NORTH AMERICAN NUMBERING AND DIALING PLANS |
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| IL-88-04-015 | NANP - SPLIT OF THE 312 NUMBERING PLAN AREA |
| Year | Number | Subject |
|---|---|---|
| IL-87-07-003 | NANP - SPLIT OF THE 617 NUMBERING PLAN AREA |
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| IL-87-03-045 | NANP - SPLIT OF THE 303 NUMBERING PLAN AREA |
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| IL-87-03-033 | NANP - SPLIT OF THE 305 NUMBERING PLAN AREA |
| Year | Number | Subject |
|---|---|---|
| IL-781-84-04-031 | NANP – SPLIT OF THE 212 NUMBERING PLAN AREA |