DESCRIPTION
The 73K321L is a highly integrated single-chip modem IC which provides the functions needed to construct a CCITT V.23 and V.21 compatible modem, capable of 0-300 bit/s full-duplex or 0-1200 bit/s half-duplex operation over dial-up telephone lines. The 73K321L provides 1200 bit/s operation in V.23 mode and 300 bit/s in V.21 mode. The 73K321L also can both detect and generate the 2100 Hz answer tone needed for call initiation. The 73K321L 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 73K321L operates from a single +5V supply with very low power consumption.

FEATURES
● One-chip CCITT V.23 and V.21 standard compatible modem data pump
● Full-duplex operation at 0-300 bit/s (V.21) or 0-1200 bit/s (V.23)
   forward channel with or without 0-75 bits/s back channel
● Full Duplex 0-1200 bit/s (V.23) in 4-wire mode
● Pin and software compatible with other TDK
   Semiconductor Corporation K-Series 1-chip modems
● Interfaces directly with standard micro processors (8048, 80C51 typical)
● Serial port for data transfer
● Call progress, carrier, precise answer tone (2100 Hz),
   calling tone (1300 Hz) and FSK mark detectors
● DTMF generator
● Test modes available: ALB, DL, RDL, Mark, Space, Alternating bit patterns
● Precise automatic gain control allows 45 dB dynamic range
● CMOS technology for low power consumption using 60 mW @ 5V
   from a single power supply