Key takeaways
- A CNAM display name holds at most 15 characters, and on Twilio it must start with a letter.
- Twilio registers CNAM through a CNAM Trust Product in Trust Hub, for US local numbers on an approved Business Profile.
- Twilio says an approved name can take 48 to 72 hours to reach US carriers.
- CNAM belongs to the number, so every call from one number shows the same name, whichever rep places it.
- Rapidialer neither reads nor changes CNAM; each number’s name is managed in your own Twilio account.
What is CNAM?
Because the lookup happens at the receiving end, the same number can show different names, or no name, depending on the carrier. Landlines and many mobile carriers do CNAM lookups, but not every carrier uses every database, and some phones rely on their own contact or caller ID apps. A change to your registered name can take days or weeks to show everywhere, because carriers cache what they find.
Branded calling is a newer, separate service, and neither replaces STIR/SHAKEN attestation: mobile networks show a display name, and sometimes a logo and a call reason, on smartphones. It needs its own registration and its limits differ by network.
For telemarketing, the caller ID itself is a legal requirement. FCC rules say a telemarketer must transmit caller ID information that includes a number and, when its carrier makes it available, the telemarketer’s name, and the number must let anyone call during regular business hours to ask not to be called (47 CFR 64.1601). A registered CNAM is how the name part reaches landlines.
Common mistakes. Choosing a name longer than 15 characters and seeing it cut off mid-word. Registering the name for your main line but not for the numbers reps actually call from. Expecting CNAM to change from call to call: it belongs to the number, so every call from that number shows the same name. And expecting it to fix a Spam Likely label, which carriers decide separately from the name.
How does a CNAM lookup work?
A CNAM lookup is a database query the terminating carrier makes when a call arrives. The carrier takes the calling number, asks a CNAM database who it belongs to, and passes the answer to the phone as the display name. The calling side does not get to choose the text on each call; it can only register a name against the number ahead of time with the provider that owns the number.
Several databases exist, run by different companies, and carriers pick which ones to query. That is why one registration can show up on a landline and a cable phone line but not on a particular mobile network.
How does CNAM registration work on Twilio?
On Twilio you register CNAM in Trust Hub, and it covers US local numbers on an approved Business Profile (Twilio: brand your calls using CNAM). The order matters, because each step depends on the one before it.
- Get a Business Profile approved in Trust Hub.
- Create a CNAM Trust Product with the display name: 15 characters or fewer, starting with a letter.
- Assign every number reps call from to that Trust Product, not only the main line.
- Wait for approval, then allow 48 to 72 hours for the name to reach carriers before you test.
- Test from a landline, since many mobile phones show their own labels.
A worked example: naming a six-number sales team
A real estate team of three reps calls from six Twilio numbers: one line assigned to each rep, a default company number, and two Chicago numbers it keeps for leads with 312 numbers. Its legal name is “Acme Realty Group LLC”, which is 21 characters, so the full name would display as “ACME REALTY GRO” and look careless. The team picks “ACME REALTY” instead, 11 characters, and assigns all six numbers to the CNAM Trust Product.
Registering only the default number would leave the five lines that do most of the dialing with no name. At Twilio’s published US rate of $1.15 per number a month (Twilio voice pricing), the six lines cost $6.90 a month.
What rules apply to the name you display?
The name must be truthful. The Truth in Caller ID Act and the FCC’s rules forbid transmitting misleading or inaccurate caller ID information with intent to defraud, cause harm or wrongfully obtain anything of value, and caller ID information includes the name as well as the number (47 CFR 64.1604). Use the business name a person would recognize from your ads, signs or emails, not a name chosen to look like a bank or a government office.
The Telemarketing Sales Rule adds that telemarketers must transmit a calling number and, when their carrier makes it available, the name of the telemarketer, and may show the seller’s name and customer service number instead (16 CFR 310.4). The FCC explains the difference between legal number display and illegal spoofing in its consumer guide. This is general information, not legal advice.
If the name does not show, check these
Work through the chain in order, from registration to the receiving phone.
- The Trust Product status is approved, and the number you called from is assigned to it.
- The call actually used that number: a rep’s line, the default number or a matching area code number can each be the caller ID.
- At least 72 hours have passed since approval.
- The receiving phone is not showing a saved contact, a carrier’s own label or a caller ID app’s guess.
- The number is a US local number; toll-free numbers go through Twilio Support instead.
CNAM in Rapidialer
CNAM is set in Twilio, not in Rapidialer, which calls through your own Twilio account. Twilio registers it through a CNAM Trust Product in Trust Hub for US local numbers on your Business Profile: up to 15 characters, starting with a letter (Twilio: brand your calls using CNAM). Calls you place through Rapidialer from those numbers then carry the name. Rapidialer does not read or change CNAM, so register every number a call can go out on: each rep’s assigned line, your default caller ID and any numbers you keep for local caller ID.
Related terms
- STIR/SHAKENThe framework US carriers use to sign and verify the caller ID on phone calls.
- Local presence dialingShowing a caller ID with the same area code as the person being called.
CNAM: questions and answers
Why does my caller ID name not show on some phones?
The receiving carrier decides whether to look the name up and which CNAM database to use. Some mobile carriers do not use the database your name is in, or show their own label instead, and phones with a saved contact or a caller ID app show that. Test from a landline first; if the name shows there, the registration works.
Can I register CNAM for a toll-free number on Twilio?
Not through Twilio’s Trust Hub CNAM registration, which covers US local numbers on an approved Business Profile. Twilio’s documentation says toll-free numbers go through Twilio Support instead. If your sales team calls from toll-free numbers, ask Twilio Support about the name before you launch a campaign, or call from local numbers you can register yourself.
How long does a new caller ID name take to show?
Twilio says an approved name can take 48 to 72 hours to reach US carriers (Twilio CNAM docs). Some carriers cache old lookups longer, so test from a landline a few days after approval before you judge whether the change has spread.
What is the difference between CNAM and caller ID?
Caller ID usually means the calling number, which travels with the call. CNAM is the name, which the receiving carrier looks up separately. A call can show the right number with no name, or a stale name from an old registration.
Can each rep show their own name with CNAM?
Only if each rep calls from their own number, because CNAM is registered per number and cannot change from call to call. A team that wants calls to show “ACME REALTY” on every line registers the same name on every number. A personal name per rep is possible on numbers assigned to one rep each, though a business name is easier for leads to recognize.
Can Rapidialer set the caller ID name for me?
No. Rapidialer places calls through your own Twilio account and does not register CNAM, read it or change it. You register the name in Twilio’s Trust Hub, and every call Rapidialer places from a registered number then carries that name. Rapidialer’s Telephony settings sync numbers bought in your Twilio account, up to 200, but not Twilio Verified Caller IDs, so check each synced number is registered.
How do I change the caller ID name on my business number?
Change the caller ID name with the provider that owns the number, because CNAM is registered per number in that provider’s records. On Twilio, edit or create the CNAM Trust Product in Trust Hub with the new display name, keep the number assigned to it, and wait for approval. Carriers cache old names, so test from a landline a few days later.
How much does CNAM registration cost on Twilio?
Twilio says it does not charge a fee to add CNAM to or remove it from Twilio numbers (Twilio Support: getting started with CNAM). You still pay for the numbers themselves, $1.15 a month for each US local number. A CNAM lookup, where you query the name behind someone else’s number, is a separate Twilio service that Twilio bills per lookup.
Does CNAM work on mobile phones?
Only in part. Some mobile networks look up CNAM for incoming calls, others show a label from their own analytics partners, and a smartphone always prefers a saved contact. That is why a name can show on a landline and not on a mobile. Branded calling, which mobile networks run separately from CNAM, is the route built for smartphone screens.