The Machine Security System (MSS) uses machine keys embedded with an electronic chip, each having a unique digital identification. The keys fit all existing Cat machines and will start them. However, on MSS-equipped machines, only keys programmed into the system will work. An antenna in the ignition switch reads the key ID. The MSS control module compares the key ID to its authorized list and signals the dash light to flash green if the machine will start and read if the key ID is not on the list. The control module sends the "start" message on to the engine or transmisson electronic control module if it is an authorized key. MSS is available as a factory-installed option or dealer retrofit on Cat skid-steer loaders, backhoe-loaders, compact and medium wheel loaders, and telehandlers. Keys can be programmed to determine who can access a machine and to limit the time frame when equipment can be started. Keys can be added to the MSS control module by plugging into the system with a laptop computer, and Cat makes a Pocket Tec system for programming keys.