Line information database
The Line Information Database (LIDB) is a collection of commercial databases used in the United States and Canada by telephone companies to store and retrieve Calling Name Presentation (CNAM) data used for caller ID services. The databases map telephone numbers to 15-character strings of caller names. Class 5 telephone switches, 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, and competitive local exchange carriers (CLECs) provide access for customers. In addition, LIDB databases were available from Neustar, TNS, Qwest, Sprint and Verisign in North America.[1] Some carriers do not provide a database, and CNAM lookups are provided using alternate methods, such as OpenCNAM or aggregated data from other sources, such as social media.
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.[2] Wholesale rates for the fee are on the order of $200 to $600 per 100,000 lookups.[2]
Per carrier policy, the name of a person or business may be automatically added to the Line Information Database and the customer must opt-out to remain anonymous. Other carriers exclude identity information by rule, and require the subscriber to opt-in. If the identity information is not available, then the maintainer of the database often returns geographic information, such as the city and state. In case of a failure, the maintainer of the database may also return "NOT AVAILABLE".
Sine there are multiple databases operated by different companies, and since it is up to the called party's carrier to perform the CNAM lookup, it is possible for one called party to receive correct Caller ID information, and a different called party to receive incorrect Caller ID information.[1] In fact, there may be multiple versions of the wrong information in different databases. The caller is responsible for contacting the owner of the database providing incorrect information and opening a trouble ticket to have the CNAM record updated.[1]
See also
External links
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- ^ a b c Monti, Greg (December 30, 2010). "CNAM for toll-free numbers". Newsgroup: comp.dcom.telecom. Usenet: 003001cba89e$f7d965f0$6801a8c0@M10023. Retrieved December 1, 2019.
- ^ a b MacIntyre, Doug (February 3, 2014). "Caller ID information wrong". Newsgroup: comp.dcom.telecom. Usenet: WIKdnRBVbcvWzm3PnZ2dnUVZ_oSdnZ2d@giganews.com. Retrieved November 26, 2019.