Title 18 of the
United States Code defines a
trap and trace device as follows: : The term "trap and trace device" means a device or process which captures the incoming electronic or other impulses which identify the originating number or other dialing, routing, addressing, and signaling information reasonably likely to identify the source of a wire or electronic communication, provided, however, that such information shall not include the contents of any communication A trap and trace device shows what numbers had called a specific
i.e.,all
incoming phone numbers. A pen register rather would show what numbers a phone had
i.e.,all
outgoing phone numbers. The two terms are often used in concert, especially in the context of Internet communications. They are often jointly referred to as "Pen Register or Trap and Trace devices" to reflect the fact that the same program will probably do both functions in the modern era, and the distinction is not that important. The term "pen register" is often used to describe both pen registers and trap and trace devices. == Relevance to USA PATRIOT Act ==