Data-flow quality control in a DSL system

The invention relates to a a data stream quality control method for digital user line communication system, wherein the communication system and wherein the transmitter and receiver with a digital user line comprising a transmitter and receiver. The transmitter data stream to powering to the receiver, Piece, according to expressing is a modulated to each data in carrier Bit number distribution, wherein the data stream to modulate to the data in carrier. The method comprises the following steps: The receiver measurement to the data stream quality, and then the data stream made of low satisfyingly condition, wherein the receiver is interface of the: transmitterLeast one Blade distribution to reduce the same number of multiple data carriers. Wires, wherein a transmitter to reduce on Bit distribution the.