Key Card Security System In a hotel, guest security is a top priority. Electronic security and alarm systems rely on sensitive - and expensive - electronic circuitry to operate. Computer scanners code key cards and read them at each guestroom. Cables connect every room to central monitoring systems. All of this equipment is vulnerable to damage from power surges and other electrical disturbances. © 2004 The Hartford Steam Boiler Insurance and Inspection Company.     All rights reserved.