The 73K302L is a highly integrated single-chip modem IC which provides the functions needed to construct a Bell 202, 212A and 103 compatible modem. The 73K302L is an enhancement of the 73K212L single-chip modem with Bell 202 mode features added. The 73K302L is capable of 1200 or 0-300 bit/s full-duplex operation over dial-up lines. 4-wire full-duplex capability and a low speed back channel are also provided in Bell 202 mode. The 73K302L recognizes and generates a 900 Hz soft carrier turn-off tone, and allows 103 for 300 bit/s FSK operation. The 73K302L integrates analog, digital, and switched-capacitor array functions on a single substrate, offering excellent performance and a high level of functional integration in a single 28-pin DIP or PLCC package. The 73K302L operates from a single +5V supply with very low power consumption.