Maryland Code, Courts and Judicial Proceedings § 10-411

(a) Law enforcement agencies in the State shall register with the Department of State Police all electronic, mechanical or other devices whose design renders them primarily useful for the purpose of the surreptitious interception of wire, oral, or electronic communications which are owned by them or possessed by or in the control of the agency, their employees or agents. All such devices shall be registered within ten days from the date on which the devices came into the possession or control of the agency, their employees or agents.

(b) Information to be furnished with such registration shall include the name and address of the agency as well as a detailed description of each device registered and further information as the State Court Administrator may require.

(c) A serial number shall be issued for each device registered pursuant to this section, which number shall be affixed or indicated on the device in question.