# Courts and Judicial Proceedings (GCJ)

## Title 10. Evidence

### Subtitle 4B. Pen Registers and Trap and Trace Devices

#### Section 10-4B-01

(a) In this subtitle the following words have the meanings indicated.

(b) "Court of competent jurisdiction" means any circuit court having jurisdiction over the crime being investigated regardless of the location of the instrument or process from which a wire or electronic communication is transmitted or received.

(c)

  (1) "Pen register" means a device or process that records and decodes dialing, routing, addressing, or signaling information transmitted by an instrument or facility from which a wire or electronic communication is transmitted.

  (2) "Pen register" does not include any device or process used:

    (i) By a provider or customer of a wire or electronic communication service for billing, or recording as an incident to billing, for communications services provided by the provider or any device used by a provider or customer of a wire communication service for cost accounting or other similar purposes in the ordinary course of its business; or

    (ii) To obtain the content of a communication.

(d)

  (1) "Trap and trace device" means a device or process that captures the incoming electronic or other impulses that identify the originating number or other dialing, routing, addressing, and signaling information reasonably likely to identify the source of a wire or electronic communication.

  (2) "Trap and trace device" does not include a device or process used to obtain the content of a communication.

(e) "Wire communication", "electronic communication", and "electronic communication service" have the meanings stated in Sec. 10-401 of this title.

#### Section 10-4B-02

(a) Except as provided in subsection (b) of this section, a person may not install or use a pen register or a trap and trace device without first obtaining a court order under Sec. 10-4B-04 of this subtitle.

(b) Subsection (a) of this section does not apply to the use of a pen register or a trap and trace device by a provider of wire or electronic communication service:

  (1) Relating to the operation, maintenance, and testing of a wire or electronic service or to the protection of the rights or property of the provider, or to the protection of users of that service from abuse of service or unlawful use of service; or

  (2) To record the fact that a wire or electronic communication was initiated or completed in order to protect the provider, another provider furnishing service toward the completion of the wire communication, or a user of that service, from fraudulent, unlawful, or abusive use of service, or with the consent of the user of that service.

(c) A person who violates subsection (a) of this section, upon conviction, is subject to a fine not exceeding $5,000 or imprisonment not exceeding 1 year, or both.

#### Section 10-4B-03

(a) An investigative or law enforcement officer may make application for an order or an extension of an order under Sec. 10-4B-04 of this subtitle authorizing or approving the installation and use of a pen register or a trap and trace device, in writing, under oath or equivalent affirmation, to a court of competent jurisdiction of this State.

(b) An application under subsection (a) of this section shall include:

  (1) The identity of the State law enforcement or investigative officer making the application and the identity of the law enforcement agency conducting the investigation; and

  (2) A statement under oath by the applicant that the information likely to be obtained is relevant to an ongoing criminal investigation being conducted by that agency.

#### Section 10-4B-04

(a)

  (1) Upon an application made under Sec. 10-4B-03 of this subtitle, the court shall enter an ex parte order authorizing the installation and use of a pen register or a trap and trace device within the jurisdiction of the court if the court finds that the information likely to be obtained by the installation and use is relevant to an ongoing criminal investigation.

  (2) On service, an order issued under paragraph (1) of this subsection shall apply to any person providing wire or electronic communication service whose assistance may facilitate the execution of the order.

(b) An order issued under this section shall:

  (1) Specify the identity, if known, of the person to whom is leased or in whose name is listed the telephone line or other facility to which the pen register or trap and trace device is to be attached or applied;

  (2) Specify the identity, if known, of the person who is the subject of the criminal investigation;

  (3) Specify the attributes of the communications to which the order applies, including the number or other identifier and, if known, the location of the telephone line or other facility to which the pen register or trap and trace device is to be attached or applied, and, in the case of a trap and trace device, the geographic limits of the trap and trace order;

  (4) Contain a description of the offense to which the information likely to be obtained by the pen register or trap and trace device relates; and

  (5) Direct, upon the request of the applicant, the furnishing of information, facilities, and technical assistance necessary to accomplish the installation of the pen register or trap and trace device under Sec. 10-4B-05 of this subtitle.

(c)

  (1) An order issued under this section shall authorize the installation and use of a pen register or a trap and trace device for a period not to exceed 60 days.

  (2) Extensions of an order issued under this section may be granted upon a new application for an order under Sec. 10-4B-03 of this subtitle and upon the judicial finding required under subsection (a) of this section. An extension may not exceed 60 days.

(d) An order authorizing or approving the installation and use of a pen register or a trap and trace device shall direct that:

  (1) The order be sealed until further order of the court; and

  (2) The person owning or leasing the line to which the pen register or a trap and trace device is attached or applied, or who is obligated by the order to provide assistance to the applicant, not disclose the existence of the pen register or trap and trace device or the existence of the investigation to the listed subscriber, or to any other person, unless or until otherwise ordered by the court.

#### Section 10-4B-05

(a) Upon the request of an investigative or law enforcement officer of a law enforcement agency authorized to install and use a pen register under this subtitle, a provider of wire or electronic communication service, landlord, custodian, or other person shall furnish the investigative or law enforcement officer with all information, facilities, and technical assistance necessary to accomplish the installation of the pen register unobtrusively and with a minimum of interference with the services that the person ordered by the court accords the party with respect to whom the installation and use is to take place, if such assistance is directed by a court order under Sec. 10-4B-04(b)(5) of this subtitle.

(b) Upon the request of an officer of a law enforcement agency authorized to receive the results of a trap and trace device under this subtitle, a provider of a wire or electronic communication service, landlord, custodian, or other person shall install the device on the appropriate line and shall furnish the investigative or law enforcement officer all additional information, facilities and technical assistance including installation and operation of the device unobtrusively and with a minimum of interference with the services that the person ordered by the court accords the party with respect to whom the installation and use is to take place, if the installation and assistance is directed by a court order under Sec. 10-4B-04(b)(5) of this subtitle. Unless otherwise ordered by the court, the results of the trap and trace device shall be furnished to the officer of a law enforcement agency, designated in the court order, at reasonable intervals during regular business hours for the duration of the order.

(c) A provider of a wire or electronic communication service, landlord, custodian, or other person who furnishes facilities or technical assistance under this section shall be compensated for reasonable expenses incurred in providing the facilities and assistance.

(d) Nothing in this subtitle may be construed as creating a cause of action against any provider of a wire or electronic communication service, its officers, employees, agents, or other specified persons for providing information, facilities, or assistance in accordance with the terms of a court order under Sec.Sec. 10-4B-02 through 10-4B-05 of this subtitle.

(e) A good faith reliance on a court order, a legislative authorization, or a statutory authorization is a complete defense against any civil or criminal action brought under Sec.Sec. 10-4B-02 through 10-4B-05 of this subtitle or under any other law.

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Md. Code Ann., Cts. & Jud. Proc. (as displayed at mgaleg.maryland.gov, October 16, 2026)