Some reference material from the NANP annual report 2004:
http://www.nanpa.com/reports/NANP_AR_2004.pdfArea Code InventoryNPA codes are in NXX format, where N is any digit 2-9 and X
is any digit 0-9, yielding 8*10*10 = 800 combinations. Of these,
119 are not assignable or have been set aside by the Industry
Numbering Committee (INC) for special purposes. These 119
codes are listed below.
N11 (8) Abbreviated dialing
N9X (80) Reserved for use during expansion
of the NANP
37X and 96X (20) Reserved by the INC for future use where
contiguous blocks of codes are required
555 and 950 (2) Not used as NPA codes to avoid
possible confusion
880-887 and 889 (9) Set aside for next series of toll-free codes.
Subtracting 119 from 800 leaves 681 assignable NPA codes. Of
these, 366 have been assigned. Of these 366, 326 are in service
and 40 are awaiting introduction. Of the 326 NPA codes in
service, 316 are geographic and 10 are non-geographic.
Of the 681 assignable NPA codes, 315 are currently unassigned.
Of these codes, 49 are easily recognizable codes (ERCs)
currently allocated for non-geographic use, and 266 are
general-purpose codes. Of these 266, 163 are reserved (*1) for use
as future geographic codes, leaving 103 available, unreserved
general-purpose codes.
Of the 49 unassigned ERCs, 12 are reserved (*2), leaving 37 available.
NPA Reserved Codes are Listed Below.220
221
223
232
235
236
238
241
247
249
257
258
259
261
263
271
272
273
274
279
280
286
287
326
327
328
329
332
343
346
353
354
357
359
363
365
367
368
382
384
387
389
421
427
428
429
431
436
437
439
445
448
449
451
453
457
458
460
461
463
468
471
472
474
476
481
483
485
486
487
489
522
531
533
534
535
536
537
539
544
546
548
558
565
566
568
572
575
576
577
579
581
582
584
587
588
622
625
629
633
634
637
639
640
644
645
652
655
665
672
673
676
677
680
681
683
685
686
688
699
721
728
729
730
735
739
742
743
745
746
748
749
750
751
752
753
761
762
768
782
789
820
821
824
825
826
837
838
839
840
841
851
854
861
871
873
875
879
921
923
924
926
927
929
930
934
938
942
945
946
948
953
974
981
982
986
*1 These codes have been designated for the relief of NPAs that NRUF
predicts
will exhaust in the next 10 years. Please note that NANPA previously
reserved codes for those NPAs projected to exhaust in the next 20 years, but
INC agreed in 2004 to reduce the time frame to 10 years. Also included are
20
additional codes reserved for use in Canada at the request of the CRTC.
*2 These include six codes reserved for Personal Communications Service
(500)
expansion and six codes reserved for Canada. Canada has also reserved 699,
which is counted as an expansion code.
Non-Geographic NPAs in ServiceThe table below lists the non-geographic NPAs in service as
of December 31, 2004, along with the service for which each
is used.
NPA Service
456 Inbound International
500 Personal Communications Service
600 Canadian Services
700 Interexchange Carrier Services
710 US Government
800 Toll-Free
866 Toll-Free
877 Toll-Free
888 Toll-Free
900 Premium Services
NPA codes 855, 844, 833, and 822 have been assigned for use as
toll free codes and will be introduced as needed.
NPA code 456 allows callers to select a carrier for international
calls terminating in a NANP country. Carriers implement this
service by activating 456 numbers in each country of origin.
500 numbers are used for "follow me" personal communications
services. Personal communications service is defined more
formally as a set of capabilities that allows some combination of
personal mobility, terminal mobility and service
profile management.
NPA code 700 was assigned in 1983 for use by all interexchange
carriers. Each carrier has the use of all 7.92 million numbers in
the 700 NPA. When a call is made to a 700 number, the local
exchange carrier passes the call to the caller's interexchange
carrier, selected either through presubscription or override.
Note that 700 numbers, unlike other NANP numbers,
may terminate in different ways, depending on how the
interexchange carrier has allocated the numbers.
900 numbers are used for premium services, with the cost of
each 900 call billed to the calling party.
In 2004, NPA codes 880, 881 and 882 were returned to the NPA
inventory and are now set-aside for future toll free service.
These codes were used for "paid toll-free service," a service
that permitted callers in one NANP countries to call toll-free
numbers in another NANP country by dialing 880 in place of
800, 881 in place of 888, or 882 in place of 877.