Abstract: An electronic computer linkage interface control security system that allows a remote computer terminal to control the across to a main computer. The system includes a Computer Linkage Interface Control (CLIC) module that is coupled to the terminal and that generates and stores a random or pseudo-random coupling code that is unique to the terminal and unique for each communication session. The computer, in which the coupling code for the current communications session was stored during the previous session, accesses the current coupling code store in the CLIC module for comparison with the computer's previously stored code. If a match occurs, access by the terminal to the main computer is permitted.