Abstract: A transmitter for sending a data transmission signal to an f electric net, whereby the apparatus comprises signal-shaping and adjustment devices (3) and connecting devices (50) including necessary accessories for connection to the electric net, signal amplifiers (20) and a connecting cable between the transmitter and the connecting point of the electric net, as for instance 230 V, 50 Hz phase rail (L) and zero rail (N) or a wall outlet as connecting points. The apparatus is divided into two or several parts, at least a first part (3) and a second part (TX/REMU), whereby second part (TX/REMU) includes at least connecting a unit (50) for connection to the electric net and a connecting cable and for connecting said second part to the electric net, whereby the length (LW) of connecting cable is under 5 m.

Abstract: Method in low voltage net data transmission system for keeping the signal level of transmission constant on the net voltage rail or on wall outlet. In the method the feedback signals are taken wired or wirelessly from one or some locations of the actual apparatus or supply cable to the measuring and handling unit (60) of transmitting signals and further to the process unit (70) of sample and holding circuits (S & H) or of corresponding means and control means (CONTROL), by which unit the control signal (URC) and/or ULC) is taken to steer the output signal or output voltage of blocks (10, 20, 40 and/or 50) in a depending way from load impedance (ZLOAD) and from the series impedance (ZW) of supply cable (LW) so that the amplitude (ULOAD) of transmission signal level (ULOAD) on voltage rail or some location of the supply cable or on wall outlet is constant or almost constant.