LUD (Local Usage Details) is a detailed record of local calls made and received from a particular phone number. These records are regularly available to police in the United States with a court order, and were traditionally subject to the same restrictions as telephone tapping. LUDs may be legally used by the police without first obtaining a warrant, as determined by Smith v. Maryland (1979). Other terms for call records include CDR (Call Detail Records) or SMDR (Station Message Detail Recordi… (More on Lud)