Abstract: A system for interconnecting an intelligent controller to a plurality of terminal devices includes a software module, a microprocessor and a device adapter having a plurality of output ports. The system operates under the control of said software module. When the system is powered up, a status for the output ports is assumed and tested under control of a configuration register. If the test is successful, the terminal port remains in that state; if unsuccessful, the state of the terminal port is reversed. The system permits an exchange of operating modes in the terminal devices associated with one port without adversely affecting operation of the remaining ports in the system.