Patent ID: 7660343

Claim:
A method of data transmission, comprising: determining and storing at least one transmission method, with at least one transmission speed that represents a maximum data throughput rate, in a table saved in at least two transmission units, for different parameters of lines; in the two transmission units, measuring and analyzing interference of a line connecting the two transmission units; in one of the two transmission units, selecting at least one transmission method based on the analysis; using the two transmission units to measure line parameters of the line using the at least one transmission method; in at least one of the transmission units, comparing the measured line parameters with the line parameters stored in the table; and in at least one of the transmission units, determining and selecting the transmission method having a transmission speed as a function of the comparison; wherein before the start of a data transmission, a measurement procedure is initiated, the procedure comprising: determining which end of the line is a central end and which end of the line is a decentral end, measuring interference of the line before other ones of the line parameters are measured at the central end, selecting and reporting a transmission method to the decentral end, sending a predetermined test signal by the central end, at two different frequencies, based on the line parameters stored in memory for the selected transmission method, and the line parameters of the test signal are measured by the decentral end, and a test signal is transmitted to the central end by the decentral end, checking an attenuation of the test signal at the central end, and, as function of the measured attenuation, additional test signals at two different frequencies are transmitted to the decentral end, wherein the attenuation is one of the line parameters and repeating the sending and checking until the line parameters stored in memory have been worked off.