Control panels for alarm systems should provide zones and zoning, entry and exit delay, automatic bell cutoff, opening and closing signals, and remote arming and disarming. Rechargeable power supplies are essential. The local alarm should be a visible or audible indication, such as bell, siren, or flashing red light, that an intrusion has occurred in order to scare away the intruder and bring attention to the situation. Alarms should be mounted outside in plain view and out of reach. Remote, or silent, alarms transmit alarm information to other locations such as police department, guard house, or central stantion, usually over telephone lines. Since wires can be cut, wireless devices such as radio telemetry should be considered. Derived channel devices use regular telephone lines to transmit a steady scanning signal which the monitoring facility reads; interruptions in the signal indicate a security breach. Tabular data provide detailed information on interior space protection devices, including application, operation, false alarm potential, and advantages and disadvantages. The operational theories, applications, characteristics, and considerations for interior perimeter protection devices are also given in tabular form.