A method for the monitoring of transmissions in a transmission branch of a bidirectional interface, which besides the transmission branch has a reception branch standing in connection with the transmission branch, has the steps a) sending out of information by means of the transmission branch, and b) evaluation of defined characteristics of the sent information via the reception branch of the same interface, whereby preferably depending on the evaluation of the sent information a setting of parameters of the transmission branch is effected, so that future information is sent out with use of these parameters.