By using a model of a transient response characteristic of an engine and a model of a steady-state characteristic of the engine, a disturbance estimate value is calculated. Each of the keyboards can correspond to a different need, user preference or computer application, including different language characters, different input controls, and different key configurations. The splitter end includes at least one splitter and a plurality of subscriber receptacles to which subscriber cables may be optically connected. The second scanning line is located between at least part of the first picture element and the first scanning line. For example, in a theater incoming calls can be held so the user can move to a hallway where he can answer the call and talk to the caller.