“No Caller ID” and “Unknown Caller” are two different things and should not be confused.
- Unknown Caller: This means the caller’s phone number is available and has been transmitted to your iPhone, but the number is not saved in your Contacts. Therefore, iOS may display the call as an unknown caller rather than showing a contact name. If you save that number in your Contacts, future calls from it can be identified by the saved name.
- No Caller ID: This is different. In this case, the caller has withheld or blocked their phone number, so your iPhone does not receive a specific telephone number associated with the call. Consequently, there is no number for you to save to Contacts and no way to identify the caller through your Contacts list.
In simple terms: Unknown Caller = the number is available but not saved in your Contacts. No Caller ID = the number itself has been hidden and is not provided to your iPhone.
