The present invention relates to compounds of the general formula . Each node includes a connection plate having a central port area that is adapted to form a recessed part of the finished surface of the ceiling system that is visible between adjacent suspended ceiling panels that conceal the grid members. At the end of an interference period, the wireless device can send a trigger signal indicating the start of an interference free interval to request data be sent to the wireless station until the expiration of the duration of the interference free interval. A set of algorithms of the algebraic operators is implemented to compile at least some of the first IR into a second IR, wherein the second IR comprises a data-flow language. Another embodiment includes a container with a door and a vent, and an antenna supported adjacent the vent.