The KT-300 door controller supports up to two readers, which can be installed either on a single door (to monitor both entry and exit) or on two separate doors. It provides connections for all peripheral devices necessary for a complete access control system and can be linked with other door controllers to provide control over millions of doors. Stand-alone mode protects against power or system failures and the system stores cardholder and event data, which is automatically transmitted back to the EntraPass system once the network connection is restored. Flash memory allows for firmware updates from an EntraPass workstation in just a few minutes. Built-in Combus expansion means that relay, input, and output modules can be added to connect HVAC systems, elevators, motion detectors, and more. The Combus is a communication protocol that is integral to the KT-300. It uses a four-conductor cable bus to which several expansion modules.Features Controls two doors and easily links to a network Update the firmware directly from system workstation Fast, up to 115,200 baud Ready to go, no DIP switches or jumpers to set 5V and 12V reader power Interfaces with an external alarm system Supervises battery conditions and reports low battery/no battery status to the system Automatic trouble reporting All power outputs are individually protected against short circuits and surges by a self-resetting PTC Choice of two memory capacities, 128K or 512K