When you receive a call, the telephone number calling you and the name associated with that number in the telephone company records will automatically appear on your phone or a caller ID unit attached to your phone. If you choose to answer the call, the name and number remains displayed until you or the caller hangs up.
Caller ID may not be available on all calls because of stipulations such as Caller ID Blocking and other telephone company equipment limitations.
If the telephone subscriber receives a call from a party that has activated Caller ID Blocking, these calls will be shown as "Private Caller," "Anonymous" or some other similar notation.
If the telephone subscriber receives a call that displays "out of area," "unavailable" or a similar notation, the carrier is not supplying the information, possibly due to their equipment limitations.