Bus-capable, modular connection and/or function module for controlling and/or monitoring technical processes and/or for industrial and/or building automation with a plate-like and/or block-like structure, which is designed to be combined with further connection and/or function modules to form a connection system, having the following features: a) at least one base terminal carrier for fixing to a mounting base, preferably provided with latching means (3, 4) for latching onto a mounting rail, b) at least one electronics housing that can be placed on the base terminal carrier, which comprises at least one printed circuit board and/or a stamped grid and/or a busbar arrangement, c) at least one or more bus conductor contacts (11, 12) for forwarding at least one power and/or data bus in the direction of arrangement to adjacent connection and/or functional modules arranged in rows, d) wherein at least one connection and/or functional unit is provided which is directly attachable to the base terminal carrier or the electronics housing and which has at least one, two or more separately attachable functional components, characterized in that e) the connection and/or functional unit has a frame as a holding element for at least one, two or more of the functional components, which frame has at least one, two or more slots for fastening and preferably receiving at least one, two or more of the functional components, f) wherein in the at least one or the two or more slots in each case one or more connection components can be used as the functional components, which is/are reversibly latched to the frame (21, 21'), in particular by the frame (21, 21 ') having a latching element (241, 221) and the functional component having a counter-latching element element which interact. a) at least one base terminal carrier for fixing to a mounting base, preferably provided with latching means (3, 4) for latching onto a mounting rail, b) at least one electronics housing that can be placed on the base terminal carrier, which comprises at least one printed circuit board and/or a stamped grid and/or a busbar arrangement, c) at least one or more bus conductor contacts (11, 12) for forwarding at least one power and/or data bus in the direction of arrangement to adjacent connection and/or functional modules arranged in rows, d) wherein at least one connection and/or functional unit is provided which is directly attachable to the base terminal carrier or the electronics housing and which has at least one, two or more separately attachable functional components, e) the connection and/or functional unit has a frame as a holding element for at least one, two or more of the functional components, which frame has at least one, two or more slots for fastening and preferably receiving at least one, two or more of the functional components, f) wherein in the at least one or the two or more slots in each case one or more connection components can be used as the functional components, which is/are reversibly latched to the frame (21, 21'), in particular by the frame (21, 21 ') having a latching element (241, 221) and the functional component having a counter-latching element element which interact.