Data transfer is performed serially. The EIB is essentially comprised of sensors == issuers of commands (e.g., light barriers, switches, thermostats, infra-red, wind gauges, time switches) & actuators == receivers of commands (e.g., motors, heaters, ventilators, lamps, shutters). The EIB bus cable can be laid on, in & under plaster, in pipes & cable channels, in dry, damp & wet rooms.