Will Sinch Elastic SIP Trunking Send My CNAM on PSTN Calls?

Sinch’s Elastic SIP Trunking product will forward any CNAM (Caller Name) data that you include in your SIP INVITE. However, due to the nature of PSTN call routing across multiple carrier networks, this CNAM information may not always be preserved end-to-end.

To help ensure that your company’s caller ID name is displayed to call recipients, Sinch offers an enhanced option: registering your desired caller name to each telephone number in a national CNAM database.

How CNAM Display Works

• Database-Driven Display: When you make a call, the recipient’s carrier performs a CNAM database lookup using the caller’s phone number to retrieve and display the registered name.
• LIDB Repositories: These lookups occur through CNAM repositories, which are part of what’s known as the Line Information Database (LIDB) system.
• Dependent on Recipient’s Carrier & Plan: Successful CNAM display depends on whether the recipient’s phone service supports CNAM lookups. Some carriers require a paid feature for CNAM to be shown on inbound calls.
   

Best Practices for CNAM Delivery

• Include CNAM in the SIP INVITE when placing outbound calls. For best success, Sinch recommends placing the CNAM data into SIP privacy headers such as Remote Party ID (RPID) or P-Asserted- Identity (PAI).
• Consider registering CNAM values with Sinch for each number to improve reliability across networks.
• Ensure that your use of CNAM complies with all applicable telecom regulations and anti-spoofing requirements.
   

Learn more

• Elastic SIP Trunking Product Information.