A transmitting/receiving unit for asynchronous data transmission has a CRC unit and a transmission FIFO in a transmission path. A coding unit for SLIP-coding of data to be transmitted can optionally be connected in the transmission path. Furthermore, a CRC unit and a reception FIFO are arranged in the reception path of the module. A decoding unit for SLIP-decoding of received data can optionally be connected in the reception path. The unit is connected to a data bus, in which case a DMA unit can also be connected to the data bus.