Law Dictionary

pen register

noun pen reg·is·ter

Legal Definition of pen register

  1. :  a device that registers the numbers dialed from a telephone — compare wiretap

Additional Notes on pen register

A court order is always required for the use of a pen register in a criminal investigation, but such use has not been considered a search or interception of communication by the U.S. Supreme Court. Some states have disagreed and discern a privacy interest in such information.

Origin and Etymology of pen register

perhaps from the original use of a pen to mark the dots or dashes used in counting the numbers dialed

Seen and Heard

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a rounded knoll or a ridge of ice

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