Window or door, and building wall comprising said window or door

A building wall having at least one opening in which a window or door is accommodated, the window or door, comprising:

• (a) a frame or casing;
• (b) at least one sash (3) formed of portions of a hollow-chamber profiled element (4);
• (c) a planar element (11), which is accommodated in the sash (3), the planar element comprising a functional element (13), the light transmission properties of which can be varied at least in some regions when a voltage is applied;
• and
• (d) a control element (12;
• 12′), which is configured to control the functional element (11);
• wherein
• the control element (12;
• 12′) is of a multi-part design and at least one constituent part (12) of the control element (12;
• 12′) is at least partially accommodated in a hollow chamber (5) of the sash (3),
• wherein the constituent part (12) at least partially accommodated in a hollow chamber (5) of the sash (7) is contacted via power rails, wherein the multi-part control element comprises at least one further constituent part which is at least partially accommodated in the building wall;
• wherein the constituent part of the control element at least partially accommodated in a hollow chamber of the sash and the further constituent part of the control element are connected to one another for communication;
• wherein the further constituent part of the control element are connected to one another for communication by means of a BUS connection, in particular CAN.