A subscriber line interface circuit apparatus includes an impedance bridge
coupled to a subscriber line. A first pair of current drivers is coupled
to the impedance bridge for driving a voice signal in a first frequency
range onto the subscriber line. A second pair of current drivers is
coupled to the impedance bridge for driving a data signal in a second
frequency range onto the subscriber line. The impedance bridge couples
the second pair of current drivers to the subscriber line across an
output impedance of Z1+Z2 within the second frequency range.