Midplane for data processing apparatus

A data processing apparatus, having a first plurality of circuit boards arranged generally side-by-side and a second plurality of circuit boards arranged generally side-by-side, the first plurality of circuit boards being mounted to the second plurality of circuit boards by a midplane. The midplane has a first main surface, a second main surface and a plurality of connector elements, each connector element including an array of electrical couplers that extend generally transversally to the main surfaces of the midplane. The array of electrical couplers connect data contacts on one circuit board mounted to the first surface of the midplane to data contacts of another circuit board mounted to the second surface of the midplane. The connection between the circuit boards is such that each data contact on one circuit board and the corresponding data contact of the other circuit board are in physical contact with a common electrical coupler.