The Intersil SLIC incorporates many of the BORSHT functions on a single IC chip. This includes DC battery feed, a ring relay driver, supervisory and hybrid functions. This device is designed to maintain transmission performance in the presence of externally induced longitudinal currents. Using the unique Intersil dielectric isolation process, the SLIC can operate directly with a wide range of station battery voltages. The SLIC also provides selective denial of power. If the PBX system becomes overloaded during an emergency, the SLIC will provide system protection by denying power to selected subscriber loops. The Intersil SLIC is ideally suited for the design of new digital PBX systems by eliminating bulky hybrid transformers.