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Frequently asked questions about CNAM (Caller ID Name) lookup for US phone numbers on Plivo.

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What is CNAM?

CNAM (Caller ID Name) is a feature in the US public telephone network that associates phone numbers with registered names. When someone receives a call, their carrier queries the Line Information Database (LIDB) and displays the caller’s registered name.

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Where is CNAM lookup available?

CNAM lookup on Plivo works for:
  • Inbound Voice API calls on US phone numbers
  • Inbound Zentrunk (SIP trunking) calls on US phone numbers
Limitation: CNAM is only available for US numbers and inbound calls only.

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How does CNAM lookup work?

  1. Caller dials your Plivo US number
  2. Plivo queries the LIDB for the caller’s registered name
  3. CNAM data is included in the call callback payload
  4. Your application can display or use the caller name

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How do I set a default CNAM setting for my account?

  1. Navigate to Phone Numbers > Settings
  2. Enable or disable CNAM lookup as the default
  3. This setting applies to numbers rented after the change

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Can I configure CNAM when buying numbers?

Yes. During the purchase process:
  1. Go to Phone Numbers > Buy Numbers
  2. Search for US numbers
  3. During purchase, select CNAM lookup configuration
  4. If you skip configuration, the account default applies

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How do I update CNAM on existing numbers?

Single number:
  1. Go to Phone Numbers > Active
  2. Click on the US phone number
  3. Update CNAM lookup setting
  4. Save
Multiple numbers:
  1. Go to Phone Numbers > Active
  2. Select numbers using checkboxes
  3. Click Choose Action > Update CNAM
  4. Apply changes

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How do I view CNAM status for my numbers?

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Via Console

  1. Navigate to Phone Numbers > Active
  2. View CNAM lookup status column for US numbers
  3. Use filters to show only CNAM-enabled or disabled numbers

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Via API

Use the cnam_lookup parameter of the AccountPhoneNumber API: 
GET /v1/Account/{auth_id}/Number/{number}/
Response includes: 
{
  "number": "14151234567",
  "cnam_lookup": true
}

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How do I filter numbers by CNAM status via API?

Use the cnam_lookup parameter in the List Account Phone Numbers API: 
GET /v1/Account/{auth_id}/Number/?cnam_lookup=true

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What callback data does CNAM provide?

When CNAM lookup is enabled, inbound call callbacks include:
ParameterDescription
cnam_lookup_resultThe caller’s registered name (if found)
Note: CNAM data may not be available for all callers. Mobile numbers and some VoIP services may not have CNAM records.

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How is CNAM lookup charged?

CNAM lookup is charged per inbound call when enabled on a number.

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When should I enable CNAM?

Enable CNAM selectively on numbers where caller identification provides business value:
  • Customer service lines
  • Sales hotlines
  • Support numbers

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How can I manage CNAM costs?

  • Disable CNAM on high-volume numbers if caller name isn’t needed
  • Monitor CNAM charges in your monthly invoice
  • Use account-level defaults to control costs

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What if CNAM lookup returns no result?

Your application should gracefully handle cases where:
  • CNAM lookup returns no result
  • Caller has no registered name
  • Database timeout occurs

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What are the limitations of CNAM lookup?

LimitationDetails
US onlyCNAM lookup is only available for US phone numbers
Inbound onlyOnly works for incoming calls, not outbound
Database coverageNot all phone numbers have CNAM records
AccuracyCNAM data may be outdated or incorrect