The present invention relates to methods and apparatuses for managing the time slots in time division duplex (TDD) frames in an xDSL system. According to certain aspects, power savings in a TDD system operating with vectoring may be achieved with sending of quiet symbols in time slots that do not have data and through the efficient configuration of time slots with data and/or idle symbols so as to limit the amount of processing by the vectoring engine within the DO portion of each TDD frame. In embodiments, a central controller in a DPU monitors the data buffers at the transmitter input on each line and computes an optimal configuration of the time slots in the DO portion of the TDD frame to achieve an optimal balance between performance and power dissipation.