Devices systems and methods are provided for providing a deterministic remote interface unit (RIU) based on a finite state machine. The RIU emulator uses a sequence controller that is configured to receive a synchronization input and to execute a fixed list of unconditional commands in an invariable order of execution based solely upon the synchronization input. The RIU emulator also uses pre-defined or pre-certified data structures that are specific to one or more interface devices to successfully execute the at least one unconditional command of the plurality when encountered in the invariable order. As such, peripheral devices may be added, removed or updated without recertification by merely inserting pre-certified data structures into memory or deleting them.