Cassette for optical fibers

In a cassette for optical fibers, said cassette including a bottom, two first longitudinally opposite rim segments and two second, laterally opposite rim segments, said rim segments projecting from the same side of the bottom and substantially around a periphery thereof, said rim segments delimiting four corners of the cassette, and at least partially an access channel for the fibers at at least one of the corners, at least one of means on the bottom for coiling said fibers and means for holding connections between coiled fibers, and a slotted access channel element within said at least one access channel for receiving said fibers, said element having slots for individually separating the fibers in parallel and for guiding said fibers, the improvement wherein said cassette includes a block projecting from the bottom and having two side faces facing end portions of corresponding adjacent rim segments at said at least one corner, thereby forming similar double access channels having sides delimited by said two faces of said block and said facing end portions of said adjacent rim segments and constituting sidewalls of two separate access channels at said at least one corner, and wherein said access channel element is sized to fit each of said double access channels for selective positioning within a given one of said double access channels.