“Police alarm system” means any mechanical or electrical device which is designed or used for the detection of unauthorized entry into a building, structure, or facility or for alerting others of the commission of an unlawful act within a building, structure, or facility, or both; and which emits a sound or transmits a message or signal when actuated. Alarm systems include, but are not limited to, direct-dial telephone devices, audible alarms, and proprietor alarms. Devices which are not designed to register alarms that are audible, visible, or perceptible outside of the protected building, structure, or facility are not included within this definition, nor are auxiliary devices installed by the telephone company to protect telephone company systems which might be disrupted by the use of alarm system. (Ord. 79-2 § 2, 1979.)