The ECPA states that law enforcement officers are not required to obtain wiretap-type court orders to use pen registers and trap and trace devices. A pen register device records telephone numbers dialed from the phone targeted by the device. A trap and trace device determines the phone number from which a call is made. Although not required to obtain a wiretap order or search warrant to use these devices, a law enforcement officer must make written application, under oath, to a court of general criminal jurisdiction for proper authorization to use either device. In the application, the agency conducting the investigation must be identified, and the relevancy of the anticipated information to the criminal investigation must be affirmed. The officer must also follow certain procedures to obtain both communications which have been stored by telephone and computerized message companies and transactional records of communication services, which include billing information and nonpublic or unlisted subscriber information. To obtain nonpublic information, the officer must present the appropriate telephone company with either a fourth amendment search warrant, a subpoena, or a court order. In the absence of implied or actual consent to stored message acquisition, an officer must present a search warrant to the communication service provider. 59 footnotes.