Subscriber station (10; 30) for a serial bus system , having a communication control device (11; 31) for controlling communication between the subscriber station (10; 30) and at least one other subscriber station (10; 20; 30) of the bus system , and a transceiver device (12; 32) for transmitting a transmit signal (TXD) generated by the communication control device (11; 31) onto a bus of the bus system , with the result that, for a message which is exchanged between subscriber stations of the bus system , the bit time (t_bt) of a signal transmitted onto the bus in the first communication phase differs from a bit time (t_bt) of a signal transmitted in the second communication phase , wherein the communication control device (11; 31) is designed to generate the transmit signal (TXD) according to a frame (450; 450_1; 4500) which serially has, after a start bit (SOF), an arbitration field , a control field and a data field and in which a field for a header checksum (H_CRC) is provided temporally in front of a field for a frame checksum (F_CRC), wherein the communication control device (11; 31) is designed to calculate the header checksum (H_CRC) from all bits in the header of a frame (450; 450_1; 4500) formed for the message , with the exception of fixed stuff bits which were inserted into the header of the frame (450; 450_1; 4500) according to a fixed bit stuffing rule, according to which a fixed stuff bit should be inserted after a fixed number of bits, and wherein the communication control device (11; 31) is designed to calculate the frame checksum (F_CRC) from all bits which are arranged in front of the frame checksum (F_CRC) in a frame (450; 450_1; 4500) formed for the message , with the result that the frame checksum (F_CRC) is also calculated from the bits in the field of the header checksum (H_CRC). a communication control device (11; 31) for controlling communication between the subscriber station (10; 30) and at least one other subscriber station (10; 20; 30) of the bus system , and a transceiver device (12; 32) for transmitting a transmit signal (TXD) generated by the communication control device (11; 31) onto a bus of the bus system , with the result that, for a message which is exchanged between subscriber stations of the bus system , the bit time (t_bt) of a signal transmitted onto the bus in the first communication phase differs from a bit time (t_bt) of a signal transmitted in the second communication phase , wherein the communication control device (11; 31) is designed to generate the transmit signal (TXD) according to a frame (450; 450_1; 4500) which serially has, after a start bit (SOF), an arbitration field , a control field and a data field and in which a field for a header checksum (H_CRC) is provided temporally in front of a field for a frame checksum (F_CRC), wherein the communication control device (11; 31) is designed to calculate the header checksum (H_CRC) from all bits in the header of a frame (450; 450_1; 4500) formed for the message , with the exception of fixed stuff bits which were inserted into the header of the frame (450; 450_1; 4500) according to a fixed bit stuffing rule, according to which a fixed stuff bit should be inserted after a fixed number of bits, and wherein the communication control device (11; 31) is designed to calculate the frame checksum (F_CRC) from all bits which are arranged in front of the frame checksum (F_CRC) in a frame (450; 450_1; 4500) formed for the message , with the result that the frame checksum (F_CRC) is also calculated from the bits in the field of the header checksum (H_CRC). <EOS>