Carrier Identification Codes (CIC)

Author: Anagha Ravi

What is a Carrier Identification Code?

CIC, short for “Carrier Identification Code,” is a unique four-digit code given by the North American Numbering Plan Administrator (NANPA) to carriers and other entities.

As a unique identifier, a CIC is used for billing purposes and routing calls over the interconnected public switched telephone network (PSTN). CIC codes are used primarily in long-distance (LD) and Toll-Free (8YY) call flows.

History of Carrier Identification Codes

The first attempt to unify numbering plans dates back to the 1940s when AT&T devised what is now known as the North American Numbering Plan (NANP) for the Bell System and other regional network operators. The Bell System needed a cohesive dialing structure for its companies and long-distance communication.

The North American Numbering Plan Administration (NANPA) ownership was transferred several times, landing with Neustar in the late 1990s and Somos in 2019. Somos is the same company that manages toll-free number administration within the North American Dialing Plan (NADP). CIC assignment for toll-free voice calls is pre-subscribed and managed within the SMS800 database, also managed by Somos.  

With the first significant overhaul of dialing procedures in the late 1980s, NANPA introduced and mandated dialing area codes in long-distance calls. Furthermore, the need to numerically identify carriers led to the introduction of CICs. 

Initially, CICs were three digits long. However, within ten years of its introduction, the three-digit system seemed to limit the number of carriers who could enter the market. Unlike the days of The Bell Systems monopoly, the ability of smaller entities to join had rapidly expanded.

How does CIC work? 

NANPA assigns a CIC to all qualifying entities (see: Who Qualifies for a CIC?). However, for dialing long-distance calls, it is not the CIC but the CAC that is used. For that, the originating party prefixes 101 to the CIC. When dialing a long-distance call, you can force a call to be routed to a carrier by prefixing the phone number with a provider’s CAC. For instance, if a carrier’s CIC is 3877, then 1013877 is its CAC. This CAC, when entered before a phone number, leads to the call being routed to this specific carrier.

When making toll-free calls, the originating (“from”) party dips the SMS800 database to determine which CIC (toll-free network provider, aka IXC) the toll-free voice call should route through. Once that is determined, the originating side of the call will route the call destined to a toll-free number to the toll-free IXC. The toll-free number owner assigns which CIC code the inbound toll-free voice call routes to.

Is CIC the same as CAC?

No, CAC stands for “Carrier Access Code,” and is formed by incorporating a 101 prefix to a carrier’s CIC. While the CIC identifies each unique carrier network, the CAC is used by the calling party, or subscriber, when making long-distance (LD) calls through those carrier networks. A CAC is not used when dialing or routing toll-free (8YY) calls.

CIC vs. PIC: What’s the difference?

Primary Interexchange Carrier (PIC) is a consumer’s primary service provider, although PIC may also be referred to as the “pre-subscribed” carrier, as the calling party/subscriber pre-selects which long distance (LD) carrier they wish to use. All PICshave CICs. The acronyms “PIC” and “CIC” are verbally used interchangeably. While local calls route across local networks, a subscriber has the choice to “PIC” or route their long-distance traffic through another LD provider. (Remember when you paid a separate company for long-distance calling plans?)

The rise of VoIP infrastructure has largely eliminated the need to “PIC” 1+ long-distance traffic to a pre-subscribed long-distance carrier. Subscribers less and less have a designated LD provider and more often pay one single phone carrier for both local and long-distance calls. Note that the calling party, or the “subscriber” that chose which PIC to work with, is paying for the outbound calls.

VoIP providers most often use the acronym “CIC” to describe a component of a toll-free call flow. Similar to how a long-distance call traverses specific networks based on which “PIC” was chosen, toll-free calls are routed to specific toll-free network owner/operators based on their “CIC” code. CIC Codes, for toll-free calls, are also “pre-subscribed” by the toll-free number owner. While the originating subscribers choose which PIC to route their LD traffic through, the receiving subscriber chooses which CIC to route their inbound toll-free calls through. This distinction mimics who pays for the voice call. The originating subscriber (the “from” caller), pays for long-distance calls, while the receiving subscriber (the “to” caller) pays for toll-free calls.(Remember when you dialed a business’ toll-free number so that you could avoid paying long-distance charges?)

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Who qualifies for a CIC?

With the expanded capacity, the NANPA can now assign a CIC to the following:

  • Local phone companies certified from the relevant state’s public utilities commission. 
  • Registered Switchless Resellers.
  • Clearinghouses (collection and billing).
  • Interconnected VoIP Providers.

Additionally, purchasers of Feature Groups B or D access are also assigned a CIC. It is worth noting that the access purchaser must confirm the purchase by presenting the citing Access Service Request (ASR).

CIC availability is one of the most critical factors that hold up the telecom industry’s regulatory and tariff based structure. The FCC’s authority is solidified by NANPA’s ability to assign and reclaim CICs. Separate CIC pools are maintained Feature Group B access and Feature Group D Access, to manage availability. 

CIC Guidelines

CIC assignment guidelines are determined by ATIS, an industry group that helps set industry accepted guidelines for networking rules, local number administration rules, porting guidelines, toll free number administration best practices, and more. 

Key takeaways: CICs

The CIC is a necessary part of the dialing, billing, and routing process for all voice service providers today – regardless of whether or not that company is AT&T, a regional bell operating company (RBOC), an incumbent local exchange provider (ILEC), interexchange carriers (IXC), interconnected VoIP providers (iVoIP), over the top (OTT) providers, or any other communications platform provider.

The NANPA expanded the region’s dialing capacity with its introduction and one impact of CIC routing today is seen by the subscriber’s ability to pre-select both long-distance and toll-free voice providers. Moreover, the precedent of adding a digit to the three-digit CIC to make a four-digit code opens up the possibility of five-digit CICs in the future. However, with reclaiming policy for unused CICs and industry trends, this does not seem likely.

Terms related to CIC

Learn more about CICs with Bandwidth

Bandwidth uses CIC codes to route toll-free calls to our customers. Bandwidth is a RespOrg with multiple service partners which gives us the ability to not only route calls based on quality and cost, but also quickly reroute traffic in the unlikely event of a service impairment.