What is the difference between Caller ID and CNAM?

The Caller ID (CLID or CID) is the actual phone number calling in, whereas the accompanying text that provides the identifying name for that number is referred to as CNAM (Caller Name).


How do Caller ID (CLID or CID) and Caller Name (CNAM) work together?

When a phone call is made, the Caller ID (CLID) is routed to the destination’s carrier for delivery. The Caller Name (CNAM) text data is not sent out by the originating carrier, as they are separate services.

When the call arrives, the carrier for this destination end of the call will reference that number against its own local CNAM database. At this point, both a Caller ID (CLID) number and Caller Name (CNAM) text is delivered to the recipient’s phone when it rings through.


What is a CNAM Database?

CNAM databases (Line Information Databases) are official, authoritative sources where the CNAM text data is recorded for any given phone number. There are multiple CNAM database providers that maintain these centralized records, and carriers may subscribe to one or several of them.


What are the limitations of the Outbound Caller Name (CNAM)?

• The Outbound Caller ID Number must be a local landline number.
• Toll free numbers are not supported.
• Maximum of 15 characters (including spaces) for the text string and will be presented as capital letters.
• Special characters are not supported.
• CNAM is applied to all local numbers within the account.
• CNAM cannot be set for individual numbers or Digital Line.
• Mobile numbers do not support CNAM. If the receiving party is a Mobile number, only the number will display.
• When the Outbound Caller ID is set to Blocked, the call recipient will see UNKNOWN or ANONYMOUS as the Caller ID/Caller Name.

IMPORTANT: As CNAM transmission is the responsibility of the terminating carrier (number being called), that terminating carrier must support CNAM functionality and must have updated CNAM Database records.