Flowroute transmits the Caller ID Number based on the presence of one of the following header fields in order of preference.
CNAM - is controlled separately in your Flowroute account for US numbers. To set CNAM, please see this article.
Caller ID - Used for non-US numbers. If the Caller ID is used, the CNAM will be passed along with the SIP signaling. Even still, it is not guaranteed to be intact as the call traverses the public telephone network (PSTN).
P-Asserted-Identity - This is a header you define through your PBX. If you have established it correctly you will see in your SIP signaling, the header with your CNAM in quotes and followed by your contact.
Remote-Party-ID - The RFC defining this header was considered failed. The RFC recommends not using this field. However, knowing some PBXs only support it, we list it as an option. We would advise against using it whenever possible.
From - Display name could be used to define your 'From:' tag. This will be pushed to the P-Asserted-Identity.
The Caller ID Number you send out on outbound calls are pulled from one of these four fields within the actual SIP packets sent to Flowroute's servers.
If you send Remote Party ID or P-Asserted-Identity, we will send that along with the SIP to the destinations. If none is provided, we will fill the field using the “From” header value.
These headers are the most common means of transmitting Caller ID in SIP devices. If you are having issues finding, or setting up the Caller ID Number, refer to the manufacturer's documentation for your PBX, if available.