A backplane and card assembly comprises: a backplane having optical and electrical connectors; a plurality of cards each comprising an optical receiver and electrical connectors, for fitting into the backplane to obtain operational optical and electrical connections via the backplane; and an automatic maintenance unit comprising a gripping arm configured to remove and replace cards from the backplane. Having both the optical and electrical connectors together on the backplane allows a relatively simple movement of the gripping arm to remove and replace the card.