XR-2121 Description
The, XR-2121 is designed to provide the plete modulator function for a Bell 212A type modem. The circuit accepts a synchronous serial data stream and generates either a 300 BPS frequency shift keyed (FSK) or a 1200 BPS differential phase shift keyed (DPSK) carrier signal. An on-board digital-to-analog converter provides a synthesized sine wave output.