COMMUNICATION CONTROL SYSTEM

PURPOSE:To enable a communication control system to carry out high speed response to erroneous control even when data is long in serial communication by inserting error detecting code in communication data at a certain interval. CONSTITUTION:After a transmission station sends out data Ia with a length of T following a flag F indicating the start of communication frame, the transmission station inserts an error detecting code FCSa corresponding to the data Ia. Next, data Ib following data Ia is sent out, and likewise an error detecting code FCSb is inserted. This is repeated, and when the last remaining data Ix comes, even when the data length does not meet length T, the corresponding error detecting code is added, and finally a flag F indicating the termination of communication frame is sent out. After receiving data Ia having a length of T, and whether data Ia received by the following error detecting code FCSa is correct or not is checked. If there is an error, receiving operation is stopped, a request for resending the data is processed, and if there is no error, the following data Ib is received.