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Glossary · Numbering

What is CNAM (caller ID name)?

  • Also called: caller id name, branded caller id

Reviewed by Sujan ThapaliyaLast updated

Definition

CNAM is the caller ID name displayed alongside a phone number on an incoming call. In North America the receiving carrier looks the name up in a database keyed to the calling number, so the name is controlled by registration, not sent with the call.
The three STIR/SHAKEN attestation levels, which underpin how cnam (caller id name) behaves in practice: A asserts both that the carrier knows the customer and that the customer may use the calling number, B asserts the customer only, and C asserts neither. A shared number pool can reach B at best, which is why number ownership keeps recurring in these definitions.
Attestation is the backdrop to most caller-ID and deliverability terms, cnam (caller id name) included.

In practice

How cnam (caller id name) actually works

Because the receiving carrier does the lookup, updating your CNAM record does not propagate instantly; different carriers refresh their caches on different schedules, typically within days.

CNAM is limited to 15 characters, and mobile carriers increasingly ignore the traditional database in favour of branded calling programmes that display a verified name and logo.

An unregistered number displays as bare digits or a guessed location, which measurably reduces answer rates.

CNAM also behaves differently by carrier in a way that surprises people. Some networks query a caller-name database at call time, others use their own cached copy, and a few do not display a name at all. Updating your record is therefore not instant everywhere, and the same call can show your name on one network and a bare number on the next.

Worked example

"Northgate Dental Practice" is 24 characters and arrives truncated. "Northgate Dental" is 16 and still does not fit — the limit is 15, so "NorthgateDental" or "Northgate Dntl" is the real choice.

CNAM (caller ID name): common questions

How long can a CNAM name be?
Fifteen characters. Names are truncated rather than wrapped, so a long legal entity name arrives cut off. Pick the shortened form of the brand that survives the limit and reads as a business rather than an abbreviation.
Why does my business name show on some phones but not others?
Because the display decision is made by the receiving carrier, not by you. Different carriers use different caller-name sources and different analytics providers, so the same number can show your name on one network, a bare number on the second and a warning on the third.
Can I set CNAM on a number I rent from a shared pool?
Generally not. The caller-name record belongs to the number, and on a shared pool the number belongs to the platform rather than to you. Registering a name requires numbers provisioned to you.

Sources

  1. Combating Spoofed Robocalls with Caller ID Authentication — Federal Communications CommissionThe STIR/SHAKEN framework, the attestation levels carriers sign calls with, and the mandate requiring providers to authenticate caller ID.
  2. 47 U.S.C. § 227 — Restrictions on the use of telephone equipment — Cornell Legal Information InstituteThe Telephone Consumer Protection Act itself — the consent requirements, calling-hours limits, and private right of action.
  3. ITU-T Recommendation E.164 — The international public telecommunication numbering plan — International Telecommunication UnionThe international number format, the 15-digit maximum, and how country codes and national numbers compose.

See cnam (caller id name) in the product

Branded caller ID puts your business name on the recipient's screen instead of a bare number. In North America it works through CNAM, the caller-name record attached to a number, combined with STIR/SHAKEN signing that lets the terminating carrier trust the call is really from you.

Explore branded caller idGet early access