Abstract: The present invention relates to a first transceiver unit, acting as a receiver unit, and to a second transceiver unit, acting as a transmitter unit. The first transceiver unit measures the signal to noise ratio for each tone, and determine whether a tone shall be shut off, thereby reducing interference on neighboring lines and power consumption. If so, the first transceiver unit keeps on measuring the noise level over that tone. If the ratio of the initially measured signal level to the newly measured noise level exceeds a pre-determined threshold, then the first transceiver unit requests the second transceiver unit to re-activate that tone. A new initialization sequence is transmitted over that tone for initializing the frequency domain equalizer, for measuring the signal to noise ratio, and finally for agreeing on a bit loading.

Abstract: The present invention relates to a method for data-signal quality control, a related receiver and a related transmitter in an XDSL communications system, where this XDSL communications system comprises a transmitter and a receiver. The transmitter is coupled to the receiver over an XDSL line, over which the transmitter sends a data-signal on a plurality of data carriers for carrying this data-signal from the transmitter to the receiver. This receiver analyses a quality of the data-signal received by the receiver and subsequently requests the transmitter, in case this quality of the data-signal is beneath a predefined level to improve the quality of the data-signal, by performing an equal transmit power increase over a plurality of the data-carriers. The transmitter in response to the requesting improves the data-signal by performing an equal transmit power increase over at this plurality of data-carriers.