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
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 ...
. The information could be the person's name or a company name. The caller's name can also be blocked and display “restricted”, or if technical failures occur “not available”.
In Canada, the caller name information can be applied either by the client's own equipment (PBX), or by the originating carrier. The altering of caller ID information is allowed, provided it does not violate regulations in place regarding spoofing or fraud.
In the US, the caller's name, or CNAM information, is not sent during a call. Rather, the terminating carrier is responsible for providing the Caller ID information to its customer. The terminating carrier performs a database lookup using the caller's phone number to obtain the name information to display with Caller ID. 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 $0.002 to $0.006 per database dip ($200 to $600 per 100,000 calls).
Incorrect Caller ID information can be displayed under a variety of circumstances. The customer's carrier may not perform the database lookup and may supply old information. Or, the customer's carrier may perform the database lookup but get incorrect information from the database owner. In this case, the database owner has stale information (and not the terminating carrier). Or, the Caller ID information may be
spoofed.
Incumbent Local Exchange Carriers (ILEC) usually provide the most correct information. ILECs have a huge database of their own CNAM data, and ILECs are willing to pay the CNAM database dip fee to another ILEC or a
Competitive Local Exchange Carrier
A competitive local exchange carrier (CLEC) is a North American telecommunications provider classification that emerged based on the competition model of the Telecommunications Act of 1996 in the United States. The act required the previously esta ...
(CLEC) to obtain the CNAM data.
See also
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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 ...
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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. In Canada, it is commo ...
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Local number portability
Local number portability (LNP) for fixed lines, and full mobile number portability (FMNP) for mobile phone lines, refers to the ability of a "customer of record" of an existing fixed-line or mobile telephone number assigned by a local exchange c ...
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Location Routing Number
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Dip Fee Fraud
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Signalling System No. 7
Signalling System No. 7 (SS7) is a set of telephony signaling protocols developed in the 1970s that is used to setup and teardown telephone calls on most parts of the global public switched telephone network (PSTN). The protocol also performs ...
References
External links
the 3GPP, the standardisation body for GSM and UMTS
{{Mobile telecommunications standards
GSM standard
Telecommunications infrastructure