Abstract: A connecting device is disclosed for electrically and mechanically linking multiple circuit boards arranged in two perpendicular stacks. The connecting device includes two identical connectors, each with a plurality of outwardly extended electrical socket contacts, and a pair of opposite, electrically insulative shoulders projected outwardly beyond the socket contacts. Electrical pin contacts are recessed into the shoulders. The pair of connectors can be engaged when in facing relation, with one of them rotated 90.degree. relative to the other. As the connectors are moved toward engagement, each shoulder of each connector enters into a nesting relation between the opposed shoulders of the other connector, pre-aligning the opposed pin and socket contacts. The shoulders have inclined edges at their outer faces, to assist in capturing their associated opposed shoulders and guide them, in a self-aligning manner, into the nesting relation. The connectors require a 90.degree.