Telecom Decision CRTC 2017-203

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Ottawa, 16 June 2017

File number: 8621-C12-01/08

CISC Canadian Steering Committee on Numbering – Consensus report CNRE120A regarding 555 line numbers


  1. In North America, 555 line numbers were initially assigned to local exchange carriers, primarily in support of directory assistance services (555-1212), until the creation of the Alliance for Telecommunications Industry Solutions (ATIS) Industry Numbering Committee (INC) 555 NXXFootnote 1 Assignment Guidelines (the INC Guidelines) in 1994.
  2. Under the INC Guidelines, 555 line numbers became a unique numbering resource assigned to individuals, companies, or carriers, on a national or non-national (regional) basis, for public information services.
  3. The INC Guidelines did not address how 555 line numbers would be placed in service, and a number of implementation issues subsequently arose. Unlike regular telephone numbers, there is no industry process for the interconnection, routing, or rating of 555 line numbers.
  4. Canada modified its use of 555 line numbers in the Canadian Adjunct to INC 555 NXX Assignment Guidelines (the Canadian Adjunct)Footnote 2 which was originally approved in CRTC Interconnection Steering Committee – Consensus items, Telecom Decision CRTC 2008-4, 23 January 2008 (Telecom Decision 2008-4). However, no assignments were made under it due to implementation issues.
  5. In 2016, the INC determined that it would be appropriate to reclaim as many 555 line numbers as possible and sunset (discontinue) the INC Guidelines. In particular, with only one number in service at that time and the use of 555-1212 having been grandfathered, the INC determined that the purpose for which 555 line numbers were originally intended had been accommodated by other information or communication technologies, and that demand for the resource had declined significantly.
  6. Effective 5 October 2016, the INC Guidelines were discontinued and superseded by the 555 NXX Line Number Reference Document (the INC Reference Document), effectively meaning that no additional 555 resources could be assigned in the United States.
  7. In Canada, all 555 line number assignments made prior to the issuance of Telecom Decision 2008-4 have been reclaimed because they were never placed in service, except for 555-1212, which is used for long distance directory assistance, and numbers set aside for use by the television/movie industry (555-0100 to 555-0199).

Consensus report

  1. On 27 March 2017, the Canadian Steering Committee on Numbering (CSCN) of the CRTC Interconnection Steering Committee (CISC) submitted the following consensus report for Commission approval:
    • Proposed Canadian Adjunct to 555 NXX Line Number Reference Document, (CNRE120A)
  2. In the consensus report, the CSCN proposed the Canadian Adjunct to the 555 NXX Line Number Reference Document (the proposed Canadian Adjunct), noting that the existing Canadian Adjunct refers to the INC Guidelines, which no longer exist. The proposed Canadian Adjunct would replace the existing Canadian Adjunct and states, among other things, that no additional 555 line number assignments will be made in Canada.
  3. The CSCN also submitted that it had reviewed the INC Reference Document and concluded that it could be adopted for Canadian use with the proposed Canadian Adjunct.
  4. 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

Commission’s analysis and determinations

  1. As indicated above, most assigned 555 line numbers in Canada were never placed in service. An entity that obtains such a number is expected to negotiate with carriers to obtain call routing and call termination to its service, which requires significant effort and costs. Further, the industry is not likely to agree to absorb the costs for various one-of-a-kind network and billing arrangements.
  2. Since issues related to placing 555 line numbers in service are unlikely to be resolved, it would be appropriate for the INC Reference Document to be adopted so that no further 555 resources are assigned in Canada.
  3. In light of the above, the Commission approves the above-noted consensus report and proposed Canadian Adjunct.

Secretary General

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