Telecom Decision CRTC 2018-51

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Ottawa, 6 February 2018

Public record: 8621-C12-01/08

CISC Canadian Steering Committee on Numbering – Consensus report CNRE121A regarding an update of unassignable NXXs in the Canadian Non-Geographic Code Assignment Guideline


  1. On 22 November 2017, the Canadian Steering Committee on Numbering (CSCN) of the CRTC Interconnection Steering Committee (CISC) submitted the following consensus report for Commission approval:
    • Update unassignable NXXs in the Canadian Non-Geographic Code Assignment Guideline (CNRE121A)
  2. The consensus report can be found in the “Reports” section of the CSCN page, which is available in the CISC section of the Commission’s website at
  3. In the report, the CSCN proposed an update to the Canadian Non-Geographic CodeFootnote 1 Assignment Guideline (the Guideline) to identify a number of N11Footnote 2 NXXsFootnote 3 as unassignable. As such, the CSCN recommended that the Commission approve the consensus report and the proposed update to the Guideline.
  4. As outlined in the consensus report, the CSCN indicated that all new central office code (NXX) assignments and other related data elements that facilitate the completion and rating of telephone calls within the public switched telephone network (PSTN) must be entered into the Business Integrated Routing and Rating Database System (BIRRDS). Further, each telecommunications service provider (TSP) pays for its use of BIRRDS. The CSCN also indicated that current BIRRDS edits do not allow N11 codes associated with Numbering Plan Area (NPA) 622Footnote 4 to be entered into the database.
  5. Section 3.6 of the current Guideline only identifies 911 and 555Footnote 5 as unassignable NXXs, opening up the possibility of other NPA 622-N11 codes being assigned under the current Guideline; this would require a modification of BIRRDS edits to allow the code input. Modifying BIRRDS inputs is an onerous process and changes require the approval of the Common Interest Group on Routing and Rating (CIGRR)Footnote 6 which oversees changes to the database.
  6. The CSCN noted that during its 3 October 2017 meeting the members agreed to update the Guideline to specify the remaining N11 NXXs that are unassignable to be consistent with other guidelines in Canada and the North American Numbering Plan (NANP).

Commission’s analysis and determinations

  1. The Commission notes that the CSCN has updated the Guideline to include the following NXXs as unassignable: 211, 311, 411, 511, 611, 711, and 811, and that these numbers, as well as 911, have been assigned for use as service codes. They are commonly called N11 codes because of their format and are used to provide three-digit dialing access to special services. These NXXs are also set aside and are not assigned by the Canadian Numbering Administrator (CNA) in other NPAs (i.e. NPAs other than 622) pursuant to section 3 of the Central Office Code (NXX) Assignment Guideline.Footnote 7
  2. Since the rest of the countries that are members of the NANP, i.e., the United States and many Caribbean countries, do not use these N11 codes as NXXs, it would be unreasonable to request that they modify the database system to accommodate such use by Canadian TSPs only. Therefore, the Commission considers it appropriate to identify all N11 codes as unassignable in the Guideline consistent with the rest of the NANP.
  3. Accordingly, the Commission approves the CSCN’s consensus report and the proposed update to the Guideline.

Secretary General

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