Abstract: A system for localized wireless audio communication includes a controller and headphones. The controller may be for transmitting a wireless signal representing audio information. The controller may be configured to encode the audio information. The headphones may be configured to receive the wireless signal and reproduce the audio information, wherein encoding the audio information includes providing an authentication uniquely associating the controller and the headphones, and reproducing the audio information includes verifying the authentication so that audio information represented by wireless signals from a source other than the controller is not reproduced.

Abstract: A method of building up an oxidized metal coating on a substrate in which the substrate is positioned adjacent a metal target in a chamber containing a low pressure mixture of inert and reactive gases; and a voltage having AC and DC components is applied to the target to sputter onto the substrate a thin layer of elemental metal and oxidized metal. The substrate is then moved to an oxidizing station in the chamber and the layer is subjected to reactive ions, as for example a beam of reactive ions, which oxidizes the elemental metal in the layer. The steps are repeated until an oxidized metal coating of a desired thickness has been built up.

Abstract: A step assembly and method of installing same in cast wall structures is disclosed. Tubular receptacles are disposed in place in the wall structure. Each receptacle has internal and external abutments. A step includes a pair of arms having abutments thereon which cooperate with the internal receptacle abutments to prevent step removal. A modified receptacle is insertable into a completed wall structure.

Abstract: A split attachment is provided from two substantially identical half pieces each having projections and slots adapted for wedgedly joining the respective halves together for securing tightly about an article. Means on the split half pieces may be deformed against the surfaces of the article to prevent sliding of the attachment or a loose movement between the gripped articles when the attachment is used to join two articles together such as the rods of a brass bed headboard.