Electronic surveillance

Electronic surveillance refers to either the interception of communications content (as in a conversation) also known as wiretapping, or the acquisition of call-identifying information (the number dialed). The latter activity is accomplished through the use of pen register devices, which capture call-identifying information for numbers of outgoing calls from the location of lawful interception, and trap and trace]] devices, which capture information for numbers received at the location of lawful interception, much like consumer caller ID systems.

Under current federal law, law enforcement (i.e., police or the FBI) must obtain a court order before conducting any of these activities. However, a wiretap requires a higher “evidentiary burden” than a pen register or trap and trace, including showing that there is probable cause to believe that a person is committing one of a list of specific crimes.