A method, comprising: - monitoring data communication on a plurality of lines (112-114) to establish data rates of the data communication on the plurality of lines (112-114), - based on the data rates: determining a partition (580-583) of at least one time division duplex transmission frame (501-503) of the data communication, the partition (580-583) comprising an upstream section and a downstream section and enabling discontinuous operation of the data communication comprising quiet times, said determining of the partition (580-583) further being based on an overall energy consumption of the data communication on the plurality of lines (112-114), - controlling modems (101-104) of the plurality of lines (112-114) to implement the partition (580-583) for the at least one transmission frame (501-503), and - performing a joint optimization across the plurality of lines (112-114) to determine the partition (580-583), the joint optimization comprising an objective function determined based on the overall energy consumption, the joint optimization being performed in view of a constraint determined based on the data rates, wherein the overall energy consumption is based on a sum of a power consumption of the plurality of lines (112-114), wherein the constraint includes that a sum of the number of data symbol positions in upstream, m us , and the number of data symbol positions in downstream , m ds , is smaller than the size of the time division duplex transmission frame, M F , expressed in symbols. - monitoring data communication on a plurality of lines (112-114) to establish data rates of the data communication on the plurality of lines (112-114), - based on the data rates: determining a partition (580-583) of at least one time division duplex transmission frame (501-503) of the data communication, the partition (580-583) comprising an upstream section and a downstream section and enabling discontinuous operation of the data communication comprising quiet times, said determining of the partition (580-583) further being based on an overall energy consumption of the data communication on the plurality of lines (112-114), - controlling modems (101-104) of the plurality of lines (112-114) to implement the partition (580-583) for the at least one transmission frame (501-503), and - performing a joint optimization across the plurality of lines (112-114) to determine the partition (580-583), the joint optimization comprising an objective function determined based on the overall energy consumption, the joint optimization being performed in view of a constraint determined based on the data rates, wherein the overall energy consumption is based on a sum of a power consumption of the plurality of lines (112-114), wherein the constraint includes that a sum of the number of data symbol positions in upstream, m us , and the number of data symbol positions in downstream , m ds , is smaller than the size of the time division duplex transmission frame, M F , expressed in symbols. wherein the overall energy consumption is based on a sum of a power consumption of the plurality of lines (112-114), wherein the constraint includes that a sum of the number of data symbol positions in upstream, m us , and the number of data symbol positions in downstream , m ds , is smaller than the size of the time division duplex transmission frame, M F , expressed in symbols. <EOS>