Carrier Identification Code

What is a carrier identification code?

A carrier identification code (CIC) identifies individual carriers operating within the North American numbering plan (NANP). The North American numbering plan administrator (NANP-A) assigns these unique 4-digit codes for the purposes of billing and call routing through the public switched telephone network (PSTN). 

Calls traveling through the networks of multiple carriers use the CIC, including long distance and toll-free calls. 

In the 1940s, the primary telephone company in the United States, AT&T, attempted to unify the then fragmented telephony system in the country with the North American Numbering Plan. Its administrative body, the NANP-A, provided a consistent numbering structure to simplify long-distance communications. Somos, which currently handles NANP-A duties, assigns carrier identification codes for toll-free voice calls and manages the SMS800 database accordingly. 

40 years later was the introduction of area codes, which helped identify long-distance phone numbers. An analogous rise in CICs followed for identifying individual carriers. These early CIC codes were three digits long, but the NANP-A added an extra digit to accommodate the growing market for carriers. 

Why should you care about carrier identification codes? 

The NANP-A assigns CICs to qualifying entities, including: 

  • Local phone companies 
  • Switchless resellers 
  • Clearing houses 
  • VoIP providers 
  • Those with Feature Group B or D access 

These entities must supply the NANP-A with up-to-date contact information and any organizational changes like mergers or acquisitions. 

Clearing houses specifically must provide usage information twice a year to the NANP-A. This data records access providers and billing and collection activities. 

The alliance for telecommunications industry solutions (ATIS), in addition to overseeing CIC assignment, oversees industry guidelines for networking, number porting, and toll-free best practices. It reserves separate CICs for entities with Feature Group B or D access. 

What’s the difference between the CIC and PIC? A similar-sounding term to CIC is the primary interexchange carrier (PIC), the subscriber’s primary service provider. When making a long distance call, the subscriber may use the PIC to route traffic through another long distance provider. 

The use of PIC for this purpose has mostly fallen out of use with the introduction of voice over internet protocol (VoIP), and most telephony subscribers use a single carrier for both local and long distance calling. 

Another distinction between the terms is who uses them and for what purpose. For long distance calls, the originator pays for the call and chooses a PIC to route the traffic. For toll-free calls, the recipient pays for the call and chooses a CIC to route the traffic. 

How does Sinch work with carrier identification codes? 

Sinch uses CICs to identify, bill, and route traffic to our access partners/customers. Access partners/customers include interexchange carriers (IXCs), wireless carriers, competitive access providers, and large corporate users. 

What are the benefits carrier identification codes? 

Carrier Identification Codes (CICs) streamline call routing, ensuring smooth communication. They enable accurate billing for transparent financial transactions and contribute to effective network management and regulatory compliance. CICs facilitate carrier interconnection, promoting seamless communication. Entities using CICs maintain oversight, adhere to regulations and ensure organizational transparency. Clearing houses monitor usage, enhancing the integrity of telecommunications operations. CICs enhance efficiency, accuracy, and regulatory compliance in telecommunications, benefiting service providers and end-users alike.