The Le79252 Dual Intelligent Subscriber Line Interface Circuit (ISLIC) device, in combination with an Le79228x ISLAC device, implements the telephone line interface function. This enables the design of a low cost, high performance, fully software programmable line interface for multiple country applications worldwide. All AC, DC, and signaling parameters are fully programmable via microprocessor or GCI interfaces on the Le79228x ISLAC devices.
Additionally, the Le79252 device has integrated self-test and line-test capabilities to resolve faults to the line or line circuit. The integrated test capability is crucial for remote applications where dedicated test hardware is not cost effective. When combined with Microchip's Le79114 VCP II device, an optimized chip set with additional performance features can be realized.
Monitor of two-wire interface voltages and currents supports
Internal ringing generation
Programmable DC feed characteristics
Selectable off-hook and ground-key thresholds
Subscriber line diagnostics
Foreign voltage sensing
Power cross and fault detection
Supports 85 Vrms internal ringing
3.3 V and battery supplies
Dual battery operation for system power saving
Automatic battery switching
Intelligent thermal management
Compatible with inexpensive protection networks
Accommodates low tolerance fuse resistors or PTC thermistors