As used in this part, the following definitions apply:
(1) "Pen register" means a device that records or decodes electronic or other impulses that identify a number dialed or otherwise transmitted on a telephone line to which the pen register is attached. The term does not include a device used by a provider or customer of a wire or electronic communication service for billing, or recording as an incident to billing, for communications services, such as but not limited to caller identification services, or used for cost accounting or similar purposes in the ordinary course of business.
(2) "Trap and trace device" means a device that records or decodes incoming electronic or other impulses that identify the originating number of an instrument or device from which a wire or electronic communication was transmitted. The term does not include a device used by a provider or customer of a wire or electronic communication service for billing, or recording as an incident to billing, for communications services, such as but not limited to caller identification services, or used for cost accounting or similar purposes in the ordinary course of business.