Within a CNAM lookup query ("call_party=terminating"), we may return a value in the "proposed_calling_number" field. The Proposed Calling Number will be returned when the Caller ID number you specified in the CNAM lookup partially matched what the caller stated is their calling number and the called_number is the same. This can help "fix" a Caller ID number that was modified while in-transit to you and was prefixed, postfixed, or truncated. Here's a simple example which further explains this:
- - John Smith is calling Susan.
- - John's caller ID is: 12125551234 and he is calling Susan's number: 16465557000.
- - John sends a TrueCLID call start request ("call_party=orig_call_start") including his caller ID and Susan's number.
- - When the call arrives to Susan, the caller ID received is "121255512" (missing the last 2 digits).
- - When Susan performs a CNAM lookup ("call_party=terminating") for the number "121255512", and includes her called number as "16465557000", TrueCNAM will return the proposed_calling_number as "12125551234" - the entire Caller ID number string, even though the number arrived truncated, and will also return the CNAM information for the entire string "12125551234", which would be "John Smith" in this case.