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Fundamentals / OCNs

Operating Company Numbers (OCNs) are used to identify the carrier of record for a telephone number or block of telephone numbers. OCNs are assigned by the National Exchange Carriers Association (NECA).

Each OCN is a 4-character alphanumeric code that uniquely identifies a service provider within the NANP. Some service providers operate multiple OCNs, for example AT&T Wireless operates both 6010 and 6214.

OCNs are classified into types:

  • wireline
  • wireless
  • alternative
  • ipes ("IP Enabled Service", e.g. VoIP)
  • tollFree (RespOrgs; see below)

The term "OCN" is often used interchangably with "SPID" (Service Provider ID). Although they are technically different concepts, an operating company's SPID is usually the same as its OCN.

In the NANP toll-free system, the equivalent concept is a Responsible Organization (RespOrg). The Toll-Free Numbering Administrator (TFNA) assigns each RespOrg a unique 5-character alphanumeric code. Since the distinction between toll-free and non-toll-free systems is generally not relevant to API users, NumberBarn groups all OCNs and RespOrgs together as "OCNs", with RespOrgs being classified as tollFree.

While we make every effort to keep this data accurate and up-to-date, your mileage may vary. Please contact api-support@numberbarn.com with any comments, concerns, or corrections.