Abstract: A shelf for housing printed circuit boards in which a back plane has an extension in the form of a back plane extender printed circuit board electrically connected to the back plane and extending forwards from the back plane at one side of the shelf. In a location forwardly of the back plane, the extender printed circuit board carries a connector structure which extends outwards from the extender printed circuit board and has connectors outwards from the extender printed circuit board. These connectors are accessible either from the front or rear of the shelf dependent upon connector orientation. This structure avoids the need for connectors on the rear face of the back plane thus allowing for the back plane to be located further to the rear and permitting increase in size in circuit boards to be mounted within the shelf. The connector structure is preferably detachable so as to permit its replacement with a different design of connector structure.

Abstract: In an arrangement of two keyboards or other lamellar input/output devices for a computer or telecommunications terminal, one keyboard is integral with a cabinet of the terminal and the other keyboard normally fits within a housing in an undersurface of the cabinet and is masked by the integral keyboard. To enable withdrawal of the keyboard housed within the housing for use, a rear part of the cabinet undersurface is configured to allow the cabinet to be tilted bodily backwards to allow access to the keyboard. This is then pulled from under the integral keyboard and the cabinet is returned to its stable position. The keyboard housed within the housing is returned to its stored position in a converse manner.

Abstract: An organizing tray for optical fiber splices has a plurality of grooves extending longitudinally, with resilient parts to retain packaged splices in the grooves. The tray snaps on to support tie members extending between end plates. Trays can be stacked one on another, with a top cover. Fibers are led from the cable ends into the trays via tubes. Excess fiber between cable ends and the splices is coiled in the tray and retained by a longitudinal strap. An enclosure will generally have a plurality of stacked trays, with an outer casing. Means can be provided for joining strength members in the cables. Copper conductors may also be included in the cables and are connected in the enclosure.

Abstract: A multiple cantilever spring contact switch has a plurality of cantilever spring contacts, arranged in one or more series with the spring contacts of a series each clamped at one end in grooves which have base surfaces inclined relative to each other. By this means, predetermined angular inclinations are imposed on the spring contacts, urging the contacts into a correct positional relationship. Particularly the individual contact members are positioned side-by-side at their clamping positions, the free ends of one or more contact members extended laterally to overlie each other. In another arrangement two or more contacts can be stacked, with a spacer member between adjacent contacts, the spacer member having one or more of said grooves.