AT&T created and developed the numbering section of the NANP from its initiation in 1947 until the separation of AT&T (Modification of Final Judgment) on January 1, 1984. The NANP was then overseen by Bell Communications Research Corporation (Bellcore, presently Telcordia Technologies), for the benefit of the Regional Bell Operating Companies (RBOC), from 1984 until the authorization of the Telecommunications Act of 1996 (TA-96). In this timespan, Bellcore kept up and composed the advancement of the NANP by working with controllers and industry agreement fora through the Alliance for Telecommunications Industry Solutions' (ATIS) Industry Carriers Compatibility Forum (ICCF).
Since 1996, the ATIS Industry Numbering Committee (INC) has been in charge of the specialized definition and utilization of NANP assets. Numbering plan choices in the United States are made by the Federal Communications Commission (FCC) under Section 251(e) of the Communications Act of 1934 as revised by the Telecom Act of 1996. State controllers may likewise make arrangements that don't negate FCC choices.
Also, Section 251(e) of the Communications Act of 1934 (Communications Act), as altered by TA-96, stipends the FCC entire purview over the NANP and related phone numbering issues in the United States.
The FCC has assigned the general obligation regarding the equal organization of NANP numbering assets toward the North American Numbering Plan Administration (NANPA), subject to requests from administrative experts in the nations that offer the NANP. NANPA's duties incorporate the task of NANP assets, and, in the U.S. what's more, its domains, coordination of zone code help arranging and accumulation of usage and conjecture information. NANPA isn't a strategy making the substance. In concluding on assignment choices, NANPA pursues administrative mandates and industry-created rules. In the U.S., focal office codes are doled out by the NANPA and, where material, thousands of squares are doled out by the Pooling Administrator.
Recorded NANP Evolution
• 1947: Original NANP Format and Values = N (0 or 1) X – NNX – XXXX where N = digits 2 through 9 and X = any digit of 0 through 9. At first, the NN digits in the NNX part of a NANP number had "trade" names whose initial two letters related to letters related with the NN digits on North American phone dials. (e.g., Beachwood 4 was BE 4)
• 1958: All Number Calling where the NNX was recorded as all numbers as opposed to 2-letters and 1-number.
• 1973: Initial presentation of Interchangeable CO Code NANP design: N (0 or 1)1 X – NXX – XXXX
• 1995: Interchangeable NPA codes actualized NANP position: NXX – NXX – XXXX
US Telephone Number Format and Values
The phone numbering address is a ten-digit number that comprises of the accompanying three essential parts:
1) A 3-digit Numbering Plan Area (NPA) code, normally called the region code.
2) A 3-digit Central Office (CO) code alluded to as the NXX code. The term Central Office, or CO, a code is utilized in this record due to its long-standing use and in light of the fact that the NXX organization is utilized for both CO Codes and NPA codes.
3) A 4-digit line number recently alluded to as a station number.
The configuration of a NANP Number is NXX-NXX-XXXX where N = digits 2 through 9 and X = any digit of 0 through 9. The digit positions in the NANP organization can be distinguished by in sequential order characters utilizing the accompanying configuration ABC-DEF-GHIJ, where ABC is the NPA, DEF is the CO Code, and GHIJ is the Line Number.
In this manner:
A United States phone number is a ten-digit number that contains two 3-digit codes and a 4-digit line number. The estimations of these phone numbers are the decimal digits 0 through 9.
Whenever composed or printed, these gatherings of digits ought to be outwardly isolated by dashes, spaces or periods as per ITU-T Rec. E.123 "Documentation for national and worldwide phone numbers, email locations and Web addresses" so as to make them simpler to perceive and recollect (e.g., NXX-NXX-XXXX).
At the point when a United States phone number is composed or printed as a global number, the number ought to be prefixed by "+1" and space (e.g., +1 NXX-NXX XXXX).
The structure of the North American Numbering Plan allows acceptance of nearby dial designs in each arrangement territory, contingent upon necessities. At the point when numerous NPA codes serve a territory in an overlay course of action, ten-digit (10D) dialing is required. Seven-digit (7D) dialing might be reasonable in territories with single region codes. Depending on the prerequisite of toll alarming, it might be important to prefix a phone number with 1.
A few archives characterize phone numbers and line numbers as being synonymous. In exchanging frameworks, line numbers characterize the physical area of the line property that associates a wireline client to a wireline switch. This refinement is imperative to some industry fragments. Most put away program controlled exchanging frameworks can connect different numbers with a solitary line. They can likewise relate various lines to a solitary number.
UNITED STATES N11 SERVICE ACCESS CODES
|N11 Code||Assigned Use|
|311||Non-emergency access to government|
|511||Traffic or Travel Information|
|611*||Telco Repair Service|
|711||Telecommunications Relay Service|
|811||Pipeline and Utility Safety|
|* Commonly accepted use but not yet officially assigned by the FCC|
ADDITIONAL NUMBERING NEEDS OF CMRS SERVICE PROVIDERS AND/OR OTHER NOMADIC SERVICES PROVIDERS
|ESRD||Emergency Services Routing Digit||10 digit NANP #(NPA-NXX-XXXX) or 10 digit non-dialable numbers||Identifies the cell site and sector from which a CMRS E9-1-1 call originates.|
|ESQK||Emergency Services Query Key /||10 digit NANP #(NPA-NXX-XXXX) or 10 digit non-dialable numbers||Used by non-CMRS nomadic services providers to identify and delivery specific call data to the appropriate PSAP. The ESQK also is used to look up location information associated with an emergency call instance.|
|ESRK||Emergency Services Routing Key||10 digit NANP #(NPA-NXX-XXXX) or 10 digit non-dialable numbers||In addition to identifying the cell site and sector from which a CMRS E9-1-1 call originates, also identifies and delivers specific call data to the appropriate PSAP|
|MSRN||Mobile Station Routing Number||NPA-NXX-XXXX||A number dynamically assigned on a per call basis by the serving wireless service provider to a CMRS roaming subscriber for incoming call setup purposes.This is used for signaling in GSM/UMTS technology.|
|TLDN||Temporary Local Directory Number||NPA-NXX-XXXX||A number dynamically assigned on a per call basis by the serving wireless service provider to a CMRS roaming subscriber for incoming call setup purposes. This is used for signaling in CDMA/TDMA/AMPS technology.|
UNITED STATES DIALING PLAN
|QUANTITY OF DIGITS DIALED||FORMAT||CALL TYPE||COMMENTS|
|None||Seizure (off hook)||Hot Line, Warm Line||Automatic connection to predetermined location|
|One Digit||0||Operator||Connection to LEC Operator|
|Services Vertical Services||Connection Activation of service, acknowledgment tone is returned to customer and dial tone is returned.|
|Vertical Service from Dial Pulse phone
|Activation of service, acknowledgment tone is returned to customer and dial tone is returned. Expansion of *XX|
|Seven Digits||NXX-XXXX||Local Call, where 10 digit local calls are required.||Call Completion|
|Ten Digits||NXX-NXX-XXXX||Local Call, where 10 digit local calls are required.||Call Completion|
|Eleven Digits||1 NXX-NXX-XXXX
|SSSP Call to another NANP location
PPCS Call to another NANP location
Note: These call types are routed differently dependent upon Intra- LATA or Inter-LATA jurisdictions.
|More than Eleven Digits||01 + CC + CC + Number 011 + CC +
CC + Number
CC=Country Code and City Code
|International PPCS Call
International SSSP Call
Note: These calls can be from 12 to 15 digits plus the Access Code.