PURPOSE: To shorten time required for system startup in a sales data processing by making a host controller automatically carry out the down line loading (DLL) processing of set data for a terminal only when the set data is destroyed by the DLL processing in the memory section of the terminal.

CONSTITUTION: When turning on each terminal 11-13 in order to start up a sales data processing, it can be judged whether or not set data is destroyed by the DLL processing in the memory section of the terminal. Further, from a terminal where set data is not destroyed, a request for treating the DLL is not issued to the host controller 2, but the request for DLL is issued from only a terminal where set data has been destroyed. On the other hand, the host controller 2 automatically executes the DLL processing of predetermined data for only a terminal 11-13 that issued the request for DLL treatment. Accordingly, if only a terminal 11-13 where the content of memory was destroyed by DLL processing due to hardware or software failure or the like automatically undergoes DLL processing by the host controller 2 to start up the system. Thereby, the time taken for starting up the system can be shortened.