A method for data transmission between a central office and a plurality of substations

摘要

In a data transmission system in which a first station can call up a second so as to receive a data signal from the second station, the first station causes its receiver to accept the data signal only after a predetermined time VZ since the first station has sent a call-up signal to the second station. Thus the effects of mis-synchronisation of the first station receiver due to interference signals preceding the data signal, can be avoided and the synchronising word SY2 preceding the data signal can be much shorter than in known systems so saving transmission time. The synchronisation of the receiver is held in dependence on the enabling for data signal reception so that, during the latter, correct synchronisation is assured. IMAGE