300-Baud CCITT V.21 Single-Chip Modem with DTMF Generator

The MC145444 is a silicon-gate CMOS frequency shift keying (FSK) modem intended for use with telemeter systems or remote control systems over the telephone network.

This device is compatible with CCITT V.21 and contains the entire circuit that provides a full-duplex or half-duplex 300-baud data communication over a pair of telephone lines. This device also includes the DTMF generator and call progress tone detector (CPTD).

The differential line driver has the capability of driving 0 dBm into a 600 ohm load with a single 5 V power supply.

The transmit level is controlled by the programmable attenuator in 1 dB steps.

Devices functions are controlled through a 3-wire serial interface.