Abstract: A local area network has a plurality of data stations 1 each connected to a common data channel 2 via a receiver 5, a transmitter 6 and a directional coupler 7, wherein, in order to resolve contention for the channel and at the same time providing each station with statistically an equal chance of gaining use of the channel, each station contends for use of the channel by transmitting, when the channel is free, transmission request signals in a sequence of consecutive time periods wherein in each time period the station either transmits a request or does not transmit a request according to a predetermined code. If in any time period a data station 1 transmits a request but detects no transmitted request by other stations, the station is permitted use of the channel 2. If the station 1 does not transmit in any time period and another station transmits a request, then the station aborts contention.