adjusting drive 10 can be controlled via a bus line said bus line can have a plurality of adjusting drives 10 connected to it in this manner for instance all adjusting drives mounted to a piece of furniture can be controlled via a sole bus communication line thereby the wiring expenditure is reduced which results in an improvement of the quality since the reduction of connections in the cable tree will also decrease the risk of failure further the use of bus communication units and the connection of the adjusting drives to a bus will allow for a reduction of the number of plugs and the number of plug types and sizes since the all of the mounted adjusting drives are connected via uniform plug connections further the adjusting drive itself can be standardized or use can be made of standardized adjusting drives also the diagnostic capability of all adjusting drives can be achieved in a simple manner in that by means of a diagnostic testing device all the adjusting drives and other components connected to the bus can be subjected to testing this will facilitate the process of checking for errors so that the errors can also be eliminated sooner fig1 and 4 also show the three part design of housing 12 the housing comprises a first housing member 66 with the housing 14 of motor.