A method of operating a network subscriber comprises receiving an input-data stream containing an input-transmission frame according to a field-bus protocol, where the input-data stream is received in chronologically successive data units having a defined processing width, decoding fields of the input-transmission frame by a plurality of field-processing units arranged in series, each field-processing unit decoding a predetermined field of the input-transmission frame, and generating an output-data stream comprising an output transmission frame according to the field-bus protocol from the input-data stream.