DBMR25S is a modular, high-speed, terminal-to-host communication system designed and built by ITT. DBMR25S is one of the first digital systems to use a backplane incorporating the VMEbus and consists of four major components: a controller, a communications processor, a terminal adapter, and a switch. The controller provides the necessary control logic to regulate the operations of the system while the communications processor is responsible for analyzing and routing information among the various system components and subsystems. The terminal adapter connects to the terminal through an RS-232 interface while the switch provides a high-speed path between the terminals and the host processor. This combination of components makes DBMR25S a cost-effective, robust, and reliable communications system that is capable of supporting multiple host systems and hundreds of simultaneous terminals.