Connection system for connecting a single row housing to a terminal element

A connection system to connect a single-row housing with a connecting element, the connection system comprising:

• a single-row housing having a top, a bottom and two opposite sides, the single row housing secured on the bottom to a mounting rail having a longitudinal axis, the single-row housing having a housing axis substantially perpendicular to the longitudinal axis of the mounting rail, the single-row housing having a plurality of levels disposed between the top and the bottom, each level having a face disposed on each opposite side to provide a plurality of faces, each face substantially parallel to the housing axis and having a single contact, the plurality of faces and contacts providing a plurality of connection areas on the single-row housing, each connection area provided for connecting one connecting element with the single-row housing, wherein the each connection area is connected with an electrical or electronic assembly in the single-row housing, and wherein the connecting element can connect to the connection area with the single contact being a plug contact.