ORS 165.661: When provider of communication service may use devices.

The provider of electronic or wire communication service may use a pen register or a trap and trace device:

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

      (2) To record the fact that a wire or electronic communication was initiated or completed in order to protect such 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

      (3) When the consent of the user of that service has been obtained.