The PBL 386 14/1 Subscriber Line Interface Circuit (SLIC) is a 90 V bipolar integrated circuit for use in ISDN Network Terminal Adapters and other short loop telecommunication equipment which often are remote powered, and by that, the available power is limited. The PBL 386 14/1 has been optimized for low total line interface cost, low power and requires a minimum of external components. The PBL 386 14/1 has constant current feed, programmable to max 30mA. The SLIC uses a first battery voltage for On-hook . A second battery voltage is used for Off-hook and must be connected, to reduce short loop power dissipation. The SLIC automatically switches between the two battery supply voltages without need for external components or external control. The loop current controls the switching between On-hook and Off-hook battery. The SLIC incorporates loop current, ground key and ring trip detection functions. The PBL 386 14/1 is compatible with loop start signalling. Two- to four-wire and four- to two-wire voice frequency (vf) signal conversion is accomplished by the SLIC in conjunction with either a conventional CODEC/filter or with a programmable CODEC/filter, e.g. SLAC, SiCoFi, Combo II. The programmable line terminating impedance could be complex or real to fit every market. Longitudinal voltages are suppressed by a feedback loop in the SLIC and the longitudinal balance specifications meet Bellcore TR909 requirements. The PBL 386 14/1 package is a very PCB space efficient 28-pin SSOP.