Smith v. Maryland

Citation: Smith v. Maryland, 442 U.S. 735 (1979).

The U.S. Supreme Court ruled that law enforcement officials do not need a search warrant to install a pen register, a device that records the numbers dialed from a telephone. Under the Katz standard, the Court found that people have no reasonable expectation of privacy in the numbers that they dial.

Subsequent Developments
Congress overturned this ruling in 1986 when it passed the Electronic Communications Privacy Act.