Abstract: An interconnection unit OB includes a flat member FM with connectors OC1, and flexible tongue-shaped elements T formed to be integral with the flat member FM. Conductors F each have a first end part fixed to one of the tongue-shaped elements T and a second end part fixed to the flat member. The tongue-shaped elements T and the flat member FM are formed of a layer of rigid material and each of the tongue-shaped elements T has a portion thereof that includes separated transverse strips S, which are kept together by the conductors F fixed to the tongue-shaped elements, thereby making the tongue-shape elements flexible. A stainless steel plate is fixed to the rigid layer. The interconnection unit is especially useful as an optical backpanel to interconnect optical connectors of printed boards mounted in a rack.