Abstract: An electronic subscriber junctor for connecting a subscriber line to a telephone exchange, comprising an output amplifier circuit connected to the line, first means for generating a compensation voltage proportional to a common mode voltage occurring on the line and for providing a direct current proportional to a DC component of the line current, second means for obtaining a constant current, for algebraically summing said constant current and said direct current, and for supplying to the output amplifier circuit a first control current equal to said algebraic sum of the constant current and the direct current, third means for providing from said compensation voltage, via two connecting wires and on each wire, a second control current to the output amplifier circuit so as to compensate for longitudinal currents on the line, each connecting wire carrying the first control current and the output amplifier circuit delivering on each line wire a current proportional to the algebraic sum, on each connecting wire,