The invention relates to a MOS transistors substitutive circuit having a transformer/data interface function, in particular for ISDN networks, comprising first (11a) and second (11b) power supply/transmitter blocks, the first power supply/transmitter block (11a) being connected between a voltage reference (V) and a first data interface (RX), and the second power supply/transmitter block (11b) being connected between a ground potential reference (GND) and a second data interface (TX), both power supply/transmitter blocks being connected to a supply voltage reference (VDD). The MOS transistors substitutive circuit according to the invention comprises first (12) and second (12′) MOS transistor pairs connected to the voltage reference (V), the MOS transistors being diode configured and held in their saturation range, so as to have a high A.C. impedance and virtually zero D.C. impedance, thereby minimizing power dissipation through the substitutive circuit. The invention also concerns a control and driving switch configuration for a network termination of at least first (11) and second (11′) MOS transistors substitutive circuits according to the invention, operating respectively in a first condition (“normal condition”) of operation of the network termination characterized by the presence of the polarity reverse control signal (Scrp), and a second condition (“RM emergency condition”) of operation of the network termination characterized by the absence of the polarity reverse control signal (Scrp). The control configuration selects the voltage reference being applied to the power supply/transmitter blocks.