What is CNAM?

First, let me explain how CallerID works. Each carrier who owns a number may choose to support CNAM, which is the name that shows up with CallerID when somebody calls you from that number. So if Comcast owns a number, they may upload a name to a national database provider, or they may choose not to upload a name, and instead leave the default value of City and State for that number. The process is the same here, if we own a number, we allow you to input a CNAM value, or leave it blank, and it will remain the City/State entry.

When you call out from a number, you only send the numeric digits to the carrier you are calling. No name data is transmitted. Then, the receiving carrier takes your digits, queries a database they subscribe to, and display the CNAM or City/State value they obtained from the national database, based on the number you are calling from. The receiving carrier cannot change the value in the national database for the CNAM entry, because they typically do not own the number.

When you update the CNAM value for one of your SIP.US DIDs, we will immediately update our national CNAM databases with the new value. However, be mindful that no text data is sent with the call, and it is the responsibility of the receiving carrier to update and query their database. Most carriers cache CNAM values for at least a few days so your changes will not be seen immediately. You will see your new value start to show up of the next 5-10 business days as carriers update their databases.

Therefore, if someone is calling your number at SIP.US, and you believe the name we are showing is in error, all we can do, is look in the national database, and confirm who owns the number and what value is set. If we are displaying that value, we have done our job. If we are not displaying that value, we can take corrective action to ensure we are displaying that value.

If you are calling someone from your SIP.US number, and they report that the name they are receiving is not correct, you can report that to us. We will ensure we have loaded the correct value into the national database. Then over the period of about a week, most carriers will show that new value. Once the value in the database is correct, our job is done. 


To update the CNAM value for your numbers, navigate to the DID page in your SIP.US portal. Use the pencil button next to the desired DID to edit it and fill out the CNAM field. Click submit and we will update the database!



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