In a data transmission a system controller generates a deactivation signal when a data stream between a subscriber transceiver and an exchange transceiver has no payload in either direction. Exchange-end transmission coefficients are then stored by an exchange memory. The deactivation signal is transmitted back to the subscriber-end transceiver, which then stores subscriber-end coefficients in a subscriber memory. The subscriber transceiver then sends the deactivation signal back to the exchange transceiver, which then stops data transmission. In response to detecting the stopping of data transmission, the subscriber-end transceiver likewise stops data transmission. Both transceivers are then placed in a stand-by state.