Glossary · CNAM
What is CNAM (Caller ID Name)?
CNAM (Caller ID Name) is the caller-name delivery service that shows a registered text name — not just the number — when a call comes in. Caller ID delivers the calling number through SS7 or SIP signaling, but the name is not carried with the call. Instead, the terminating carrier looks up the number in a name database and presents the matching name to the recipient. In the United States that name is capped at 15 characters and must contain at least one non-numeric character.
How CNAM works: the “dip”
CNAM names are not transmitted in the call signaling. When a call reaches the terminating (receiving) carrier, that carrier performs a CNAM “dip” — a real-time lookup that takes the calling number and queries a name database before the phone rings.
If the database returns a match, the carrier attaches that name to the call and displays it on the recipient’s device. If no match is found, the recipient sees a fallback such as the bare number, the city/state, or a generic label like “WIRELESS CALLER.”
The source database is a LIDB (Line Information Database) — a repository mapping telephone numbers to subscriber names. Each terminating carrier typically dips a single LIDB/CNAM provider, so the name a recipient sees depends on the data in their carrier’s chosen database, not the caller’s.
CNAM vs. caller ID vs. branded caller ID
These three terms are often conflated but work differently — especially on who controls the displayed name and where it comes from.
| Aspect | Caller ID (number) | CNAM (caller name) | Branded Caller ID / RCD |
|---|---|---|---|
| What displays | Calling number | 15-char registered name | Name plus logo/photo |
| Source of data | Call signaling (SS7/SIP) | Terminating-carrier database dip | Caller-supplied, signed |
| Who controls it | Originating network | LIDB/CNAM provider’s data | Calling party / enterprise |
| Spoof resistance | Low | Low (no authentication) | High — rides on STIR/SHAKEN |
Traditional CNAM is unauthenticated: it is fetched from a third-party database by the receiving carrier, so it offers no guarantee the caller is who the name claims. Rich Call Data (RCD) is the next-generation approach — the caller supplies name and logo, signed and verified through STIR/SHAKEN attestation, rather than relying on a database dip.
Why CNAM matters for business phone
For a business making outbound calls, CNAM is what turns an anonymous number into a recognizable identity on the recipient’s screen. A correctly registered CNAM record raises answer rates and reduces “who is this?” confusion.
- Outbound answer rates: a recognizable name beats an unknown number; branded calling on top of STIR/SHAKEN can lift answer rates materially for legitimate commercial callers.
- The 15-character constraint: business names must be abbreviated to fit 15 characters, so the registered string matters for brand recognition.
- Stale-data risk: because each terminating carrier dips its own provider, a name change can take time to propagate, and some carriers may still show an old name or a generic label.
- Per-DID registration: CNAM is registered per number, so multi-line businesses register the name on each outbound DID.
Common CNAM problems
Because CNAM depends on third-party databases the caller does not control, display is inconsistent. A number can show one name on one carrier and a different (or generic) name on another, depending on which LIDB each terminating carrier dips and how fresh that data is.
CNAM also does nothing to prove a call is genuine — the name is looked up from a number that may itself be spoofed. That gap is exactly what caller ID spoofing exploits, and why authenticated mechanisms like STIR/SHAKEN and RCD layer on top of (or replace) classic CNAM.
CNAM (Caller ID Name) frequently asked questions
What does CNAM mean?
CNAM stands for Caller ID Name (also called Caller Name Delivery). It is the service that displays a text name associated with a phone number when a call is received.
Unlike the calling number, which travels with the call in the signaling, the CNAM name is not transmitted — the receiving carrier looks it up in a database before presenting the call.
How does a CNAM lookup (dip) work?
When a call reaches the terminating carrier, that carrier performs a CNAM ‘dip’: it takes the calling number and queries a CNAM/LIDB database in real time before the phone rings.
If the database returns a match, the name is attached to the call and shown on the recipient’s device. If there is no match, the recipient sees the number or a generic label instead.
What is the character limit for CNAM?
In the United States, a CNAM record is limited to 15 characters and must include at least one non-numeric character. Business names longer than 15 characters must be abbreviated to fit the field.
Why does my caller ID name show the wrong name or ‘WIRELESS CALLER’?
CNAM is looked up by the recipient’s carrier from a third-party database, and each terminating carrier typically dips only one provider. If that provider’s data is stale or lacks your record, the recipient sees an old name, a generic label like ‘WIRELESS CALLER’, or just the number.
Name changes can take time to propagate across the different databases carriers use.
What is the difference between CNAM and branded caller ID?
CNAM is an unauthenticated name fetched by the receiving carrier from a database, capped at 15 characters and offering no proof the caller is genuine. Branded caller ID, built on Rich Call Data (RCD), lets the calling party supply a name and logo that are signed and verified through STIR/SHAKEN.
RCD is caller-controlled and spoof-resistant, whereas classic CNAM relies on a database dip the caller does not control.
See how DialPhone fits
DialPhone’s business phone lets you register a CNAM (Caller ID Name) on your outbound numbers so recipients see your business name rather than an unknown number, and pairs it with STIR/SHAKEN call authentication so your calls are signed as legitimate — improving answer rates without relying on a single carrier’s database staying current.