Examples here pertain to North America: If you've recorded a DID for a phone number in your Contacts as a 10-digit number, then Contact Name information for inbound calls that the PBX identifies and presents as an 11-digit number (i.e. 1 or +1 is prepended to the number) will not appear in Call History. In fact, if you have an 11-digit number in your Contacts and the incoming call DID is recorded with a + prefix, you also will not get a match and will be missing helpful Contact Name info in the Call History list. For example: an entry in Contacts for a person named "Information Please" has a phone number 2065551212. An inbound call is received from that DID, but is recorded in the Call History log as either 12065551212 or +12065551212. The inbound call data in the Call History log will show the Caller ID (11-digit or +1 format), but the name from the Contacts list will not appear in the log. This would be really helpful for users who would like to look at their Call History and see WHO called, rather than only their Caller ID.