the selected generator polynomial the function blocks shown in fig3 allow the software implemented error recognition method 102 to be checked to be move precise it is possible to establish whether there are and the size of gaps for any errors which cannot be recognized by the crc hardware the simulation of an u201c artificial u201d error is implemented using the xoring 250 of a stored crc code word with the bit sequence to be transmitted this operation is based on the property that the crc calculation for xoring two code words also delivers a code word of the crc polynomial under consideration this stimulation means is implemented essentially in hardware with a software interface which can be used to indicate the bit positions to be corrupted preferably being provided in addition it is now the aim to safely recognize even the implanted errors which remain undiscovered by the crc check using the error recognition method 102 which is in the form of software if it is not the case security gaps arise which are difficult to quantify a further improvement in security is obtained by checking the crc hardware particularly the comparator 219 in the receiver itself if the comparator 219 does not validate the crc check or validates it incorrectly the erroneous data sometimes continue to be transmitted.