The ST7538 is a Half Duplex synchronous/asynchronous FSK Modem designed for power line communication network applications. It operates from a single supply voltage and integrates a line driver and a 5V linear regulator. The device operation is controlled by means of an internal register, programmable through the synchronous serial interface. Additional functions as watchdog, clock output, output voltage and current control, preamble detection, time-out, band in use are included. Realized in Multipower BCDV technology that allows to integrate DMOS, Bipolar and CMOS structures in the same chip.