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.