The invention relates to a method and device (100) for a half-duplex transmission of data (DATA) on a signalling line (20). According to the invention, the consumer unit (30, 30') of the transceivers (10, 10') is deactivated during transmission by means of a switch (60, 60'). The data is transmitted by means of the modulation of a current source unit (40, 40') and is acquired in the receiver using a comparator unit (50, 50'). Additional comparator units (52, 52', 54, 54') and current source units (42, 42', 44, 44') are used to detect the state of a full buffer or a short-circuit of the communication path.