IAPP CIPP/US Practice Exam

Answer: A - Pen registers are surveillance devices that lawfully track phone numbers dialed and incoming calls. These surveillance devices are utilized by law enforcement but are not permitted to collect or access the content of communications or the parties to communications.
 
In a connected world, pen registers and trap devices assist law enforcement by providing a picture of an individual’s associations, habits, contacts, interests, and activities. These trace devices continually pose significant privacy concerns and debates.