Transmission device comprising: - a CPE wire line for connection to a customer premise equipment, - a telephone wire line for connection to a POTS telephone exchange through a POTS line, said telephone exchange comprising means for detecting an off-hook state when the current on the POTS line exceed an off-hook threshold, - a DC/DC power converter, - a first connecting module for connecting the DC/DC power converter to the telephone wire line or to the CPE wire line, - a second connecting module between the telephone wire line and the CPE wire line, having an open state wherein a DC component is blocked and a closed state wherein said DC component is not blocked, - a detection module powered by the DC/DC power converter for detecting a power feeding request signal on the CPE wire line, and - a switching module powered by the DC/DC converter, having an active state wherein it controls the second connecting module in its open state, and sends a power ready signal on the CPE wire line, and a stand-by state wherein it does not controls the second connecting module and does not send a signal on the CPE wire line, so that a total power consumption of the detection module and the switching module in the stand-by state is lower than a predetermined threshold, and a total power consumption of the detection module and the switching module in the active state is higher than said predetermined threshold, wherein the total power consumption of the detection module and the switching module in the stand-by state correspond to a current on the POTS line lower than said off-hook threshold, and the total power consumption of the detection module and the switching module in the active state correspond to a current on the POTS line higher than said off-hook threshold, wherein the detection module comprises means (18, 19) for controlling the switching module from the stand-by state to the active state in response to a detection of said power feeding request signal. - a CPE wire line for connection to a customer premise equipment, - a telephone wire line for connection to a POTS telephone exchange through a POTS line, said telephone exchange comprising means for detecting an off-hook state when the current on the POTS line exceed an off-hook threshold, - a DC/DC power converter, - a first connecting module for connecting the DC/DC power converter to the telephone wire line or to the CPE wire line, - a second connecting module between the telephone wire line and the CPE wire line, having an open state wherein a DC component is blocked and a closed state wherein said DC component is not blocked, - a detection module powered by the DC/DC power converter for detecting a power feeding request signal on the CPE wire line, and - a switching module powered by the DC/DC converter, having an active state wherein it controls the second connecting module in its open state, and sends a power ready signal on the CPE wire line, and a stand-by state wherein it does not controls the second connecting module and does not send a signal on the CPE wire line, so that a total power consumption of the detection module and the switching module in the stand-by state is lower than a predetermined threshold, and a total power consumption of the detection module and the switching module in the active state is higher than said predetermined threshold, wherein the total power consumption of the detection module and the switching module in the stand-by state correspond to a current on the POTS line lower than said off-hook threshold, and the total power consumption of the detection module and the switching module in the active state correspond to a current on the POTS line higher than said off-hook threshold,