Federal Communications Commission 
Washington, D.C. 20554
June 25, 2001
Mr. Ronald R. Conners
Director of NANP Administration
NeuStar, Inc.
1120 Vermont Avenue, N.W.
Suite 400
Washington, D.C. 20005
RE: Carrier Identification Code (CIO Administration 
Dear Mr. Conners:
By letter dated October 23, 1995, the Common Carrier Bureau (Bureau) directed 
the North American Numbering Plan Administrator (NANPA) to transition from three- 
digit to four-digit Feature Group D Carrier Identification Codes (CICs) to increase the 
number of CICs available for assignment.' A plan developed by the Industry Numbering 
Committee (INC) to transition from three- to four-digit CICs included a transition period 
during which common carriers could use both three- and four-digit CICs.2 In accordance 
with the plan, the NANPA was to cease assigning three-digit CICs during the transition 
period (which included their equivalent - four-digit CICs that begin with a zero), and to 
begin assigning four-digit CICs, but only those in the 5XXX and 6XXX ranges. At the 
conclusion of the transition period, a zero was added to all three-digit CICs to convert 
them into four-digit CICs. The conversion from three to four-digit CICs was completed 
successfully on December 31,1999.3
Since the limitation on assignable CICs was imposed, U.S. carriers have only 
been assigned four-digit CICs that begin with either a five or a six.4 Despite the 
restriction, a U.S. carrier has petitioned the Commission for a specific CIC beginning
1 See Letter from Kathleen M. H. Wallman, Chief, Common Carrier Bureau, to Ronald R. Conners, 
Director of NANP Administration, dated October 23, 1995. See also Administration of the North American 
Numbering Plan, Notice of Proposed Rulemaking, 9 FCC Red 2068 (1994). The Commission has plenary 
authority to administer numbering resources pursuant to section 251 (e) of the Communications Act of 
1934, as amended by the Telecommuincations Act of 1996. 47 U.S.C. § 251(e). The Bureau issued this 
directive pursuant to delegated authority. See generally 47 C.F.R. § 0.291.
2 Carrier Identification Code Assignment Guidelines, INCO 95-0127-006 (reissued January 8, 2001), p. 3 
(CIC Assignment Guidelines).
3 The transition period ended when the last common carrier converted successfully to four digit CICs on 
that date.
4 Section 251(e) gives the FCC jurisdiction over those portions of the North American Numbering Plan 
that pertain to the U.S. only. 47 U.S.C. § 251(e).
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with a zero; that petition remains pending.5 The NANPA continued to assign such CICs 
to Canadian common carriers, however, at the request of the Canadian regulatory 
authorities. Recently, the NANPA reported to the North American Numbering Council 
(NANC) that the current pool of eligible CICs in the 5XXX and 6XXX ranges will 
exhaust in approximately 18 months,6 and advised that planning should begin 
immediately to make the other ranges of CICs available for assignment to U.S. carriers.
We agree that the successful transition from three to four digit CICs, the current 
and anticipated demand for CICs, and the projected exhaust of CICs in the 5XXX and 
6XXX ranges all warrant modification to the administrative instructions issued 
previously by the Bureau. Accordingly, the NANPA is hereby directed to lift the current 
administrative restriction on assignable four-digit CICs. All available four-digit CICs, 
including those beginning with zero, shall be made available for assignment, except as 
explained below.
To ensure the continued availability of a sufficient number of CICs, the current 
limitation of two CICs per entity will remain in place at this time. Entities that already 
have assigned to them two or more CICs may not request from the NANPA additional 
CICs from any range. The Bureau may reexamine the necessity of this limitation after 
evaluating the NANC's report assessing the impact of requiring that all resellers of 
telecommunications services obtain CICs.7 The NANC submitted this report to the 
Bureau on June 18, 2001.
Entities may begin requesting available CICs in all ranges on August 6, 2001 at 
12:00 p.m. (noon) Eastern Standard Time. All properly filed CIC applications shall be 
processed by the NANPA on a first-come, first-served basis, in accordance with the INC 
Guidelines, except where the guidelines are in conflict with the directives herein.
The NANPA is directed to withhold from assignment all CICs in the 41IX and 
X411 formats.8 These CICs shall be deemed "restricted" and unavailable for assignment 
until further notice.9 The NANPA may, if necessary and after consultation with the
5 See U.S. Connect's Request for Intervention by the FCC Pursuant to Neustar's January 10, 2000 
Decision, filed March 13,2000.
6 CIC Issues Management Group (IMG) Report to the NANC, March 15, 2001 (draft).
7 See Policy and Rules Concerning Unauthorized Changes of Consumers Long Distance Carriers, Third 
Report and Order and Second Order on Reconsideration, 15 FCC Red. 15,996 (2000).
8 According to the NANPA, only one of these CICs (6411) is currently assigned.
9 In a separate proceeding, the Commission will likely address whether these CIC<; could be used to offer 
competitive directory assistance (DA) service, as an alternative to 411 presubscription. See Common 
Carrier Bureau Seeks Further Comment on Telegate's Proposal for Presubscription to "411" Directory 
Assistance Services, Public Notice, 15 FCC Red. 7563 (2000) (seeking comment cm whether a lower cost 
alternative to 411 presubscription for opening the DA market to competition would be to require all DA 
service to be provided through "1010" access codes).
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Bureau, establish interim procedures to effectuate the administrative instructions 
contained in this letter.
The Bureau intends to address other issues relating to the administration of CICs, 
including CIC reclamation and the propriety of the CIC Assignment Guidelines, 
paragraph 5.2, "Transfer of CICs," which allow entities to retain more than two CICs if 
they are acquired through mergers and acquisitions. lo In resolving these issues, we seek 
to optimize the use of these valuable numbering resources, and we look forward to the 
NANPA's continued cooperation in this effort.
Sincerely,
Dorothy T. Attwood
Chief, Common Carrier Bureau
Federal Communications Commission
CC: Robert C. Atkinson, NANC Chairman
10 As a direct result of this provision, at least one entity controls more than 100 CICs.
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