The HC5526 is a subscriber line interface circuit that is compliant with CCITT standards. Enhancements include immunity to circuit latch-up during hot plug and absence of false signaling in the presence of longitudinal currents. The HC5526 is fabricated in a High Voltage Dielectrically Isolated (DI) Bipolar Process that eliminates leakage currents and device latch-up problems normally associated with Junction Isolated (JI) ICs. The elimination of the leakage currents results in improved circuit performance for wide temperature extremes. The latch free benefit of the DI process guarantees operation under adverse transient conditions. This process feature makes the HC5526 ideally suited for use in harsh outdoor environments.