The line information database (LIDB) is a collection of commercial

databases In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases spa ...

used in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

and

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

telephone A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into e ...

companies to store and retrieve

Calling Name Presentation Caller Name Presentation (CNAP) or Caller Name Delivery (CNAM) is used in US-based telephone networks to provide name identification of the calling party. The CNAM information is most often displayed in Caller ID. The information could be the person ...

(CNAM) data used for

caller ID Caller identification (Caller ID) is a telephone service, available in analog and digital telephone systems, including voice over IP (VoIP), that transmits a caller's telephone number to the called party's telephone equipment when the call is ...

services. In Canada, it is common for the client to apply their own Caller ID information, and this is allowed (and common in PBXs), provided the regulations regarding spoofing and fraud are not violated. The databases map telephone numbers to 15-character strings of caller names.

Class 5 telephone switches {{No footnotes, date=August 2008 A class-5 telephone switch is a telephone exchange in the public switched telephone network (PSTN) that directly serves subscribers and manages subscriber calling features. Class-5 services include basic dial-tone ...

, which provide end-office services in exchange areas, use the Signaling System 7 (SS7) signaling protocol to query the database. The data submitted to the Line Information Database is maintained by a customer's carrier, and most incumbent local exchange carriers (ILECs) like the

Baby Bells The Regional Bell Operating Companies (RBOC) are the result of '' United States v. AT&T'', the U.S. Department of Justice antitrust suit against the former American Telephone & Telegraph Company (later known as AT&T Corp.). On January 8, 19 ...

, and

competitive local exchange carrier A competitive local exchange carrier (CLEC), in the United States and Canada, is a telecommunications provider company (sometimes called a " carrier") competing with other, already established carriers, generally the incumbent local exchange carrie ...

s (CLECs) provide access for customers. In addition, LIDB databases were available from Intelco, Neustar, TNS,

Qwest Qwest Communications International, Inc. was a United States telecommunications carrier. Qwest provided local service in 14 western and midwestern U.S. states: Arizona, Colorado, Idaho, Iowa, Minnesota, Montana, Nebraska, New Mexico, North Dako ...

, Sprint and

Verisign Verisign Inc. is an American company based in Reston, Virginia, United States that operates a diverse array of network infrastructure, including two of the Internet's thirteen root nameservers, the authoritative registry for the , , and gener ...

in North America. Some carriers do not provide a database, and CNAM lookups are provided using alternate methods, aggregated data from other sources, such as social media. In the USA, caller ID name information is not transmitted from the originating office to the destination office. It is the terminating carrier that is responsible for providing the caller ID information to its customers. The carrier performs a database lookup using the caller's telephone number to obtain the name information for the caller ID service. If the data is with another carrier, then the terminating carrier must perform a lookup and pay a small ''dip fee'' to the carrier hosting the information. Wholesale rates for the fee are on the order of $200 to $600 per 100,000 lookups. Per carrier policy, the name of a person or business may be automatically added to the Line Information Database and the customer must opt-out to remain anonymous. Other carriers exclude identity information by rule, and require the subscriber to opt-in. If the identity information is not available, then the maintainer of the database often returns geographic information, such as the city and state. In case of a failure, the maintainer of the database may also return "NOT AVAILABLE". The CNAM databases are independent databases operated by LECs and other private companies. The called party's carrier has the responsibility to perform the CNAM lookup, and it is possible that lookups for the same telephone number from different locations return different name information.

References

Telephony Caller ID {{technology-stub

See also

References