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Criminal Resource Manual

1062. Unauthorized Installation or Use of Pen Registers and Trap and Trace Devices—18 U.S.C. § 3121

The 1986 Act added 18 U.S.C. §§ 3121 through 3126, which regulate the use of pen registers and trap and trace devices. Section 3121(a) contains a general prohibition against installation or use of a pen register or trap and trace device without first obtaining a court order under 18 U.S.C. §  3123 or under FISA. Section 3121(c), added in 1994, requires a government agency authorized to use a pen register to use technology reasonably available to it that restricts the recording or decoding of the impulses to the dialing and signaling information utilized in call processing. Section 3121(d) provides that whoever "knowingly" violates § 3121(a) is subject to a fine as provided by Title 18 and imprisonment of not more than one year.

The statute contains provisions exempting a service provider using a pen register or trap and trace device in order to test, operate, or maintain its equipment and services, or to protect the property rights of its customers, 18 U.S.C. § 3121(b)(1), or to record the fact that a wire or electronic communication was initiated or completed in order to protect itself, another provider, or a customer from fraud or abuse. 18 U.S.C. § 3121(b)(2). Finally, it is not necessary to obtain a court order when the telephone user consents to the installation of the pen register or trap and trace device. 18 U.S.C. § 3121(b)(2).

[cited in USAM 9-60.200]