The present disclosure relates to a telecommunications device. The telecommunications device includes an electrical balance duplexer connected to an output node of a transmission path, an input node of a receive path, an antenna, and a tunable impedance. The electrical balance duplexer is configured to isolate the transmission path from the receive path by tuning the tunable impedance. The telecommunications device also includes a tuning circuit for tuning the tunable impedance. The tuning circuit includes amplitude detectors for measuring voltage amplitudes, phase detectors for measuring voltage phase differences, an impedance sensor for measuring an input impedance of the electrical balance duplexer, and a processing unit operatively connected to the detectors, the impedance sensor, and the tunable impedance. The processing unit is configured to calculate an optimized impedance value. The processing unit is also configured to tune the tunable impedance towards the optimized impedance value.