plu such as described in german patent application no de 44 16 881 a1 or by other internal cells of the unit into the memory of the switching table the configuration data can also be simultaneously transferred by the plu or other internal cells of the unit to several different switching tables in order to allow the switching tables to load simultaneously the configuration data can also be in the main memory of a data processing system and be transferred by known methods such as dma or other processor controlled data transfer instead of the plu after the plu has loaded the ring memory of the switching table the controller of the switching table is set to a start status which establishes a valid configuration of the complete unit or parts of the unit the control of the switching table starts now with repositioning of the read position pointer and or the write position pointer as a response to events taking place in order to cause new data to be loaded into the switching table or a number of switching tables the controller can return a signal to the plu as described in german patent application no de 44 16 881 a1 or other parts of the unit that are responsible for loading new data into the ring memory of the switching table such a feedback can be triggered by the analysis of a special command a counter status or from the outside the state back unit described in patent application pact02 the plu.