Low-speed Modems

General Description

The 73K222BL is a highly integrated single-chip modem IC which provides the functions needed to construct a CCITT V.22, V.21, Bell 212A and Bell 103, compatible modem, capable of 1200 bit/s full-duplex operation over dial-up lines. The 73K222BL is an enhancement of the 73K222AL single-chip modem which adds the hybrid hook switch control, and driver to the 73K222AL. In Bell 212A mode, the 73K222BL provides the normal Bell 212A and Bell 103 functions and employs a 2225 Hz answer tone. The 73K222BL in V.22 mode produces either 550 or 1800 Hz guard tone, recognizes and generates a 2100 Hz answer tone, and allows 600 bit/s V.22 or 0?300 bit/s V.21 operation. The device integrates analog, digital, and switched-capacitor array functions on a single substrate, offering excellent performance and a high level of functional integration in a 32-Lead PLCC package. It operates from a single +5 V supply.
The 73K222BL includes the DPSK and FSK modulator/demodulator functions, call progress and handshake tone monitor and a tone generator capable of tones required for European applications. This device supports V.22 (except mode v) and V. 21 modes of operation, allowing both synchronous and asynchronous communication. Test features such as analog loop, digital loop, and remote digital loopback are supported. Internal pattern generators are also included for self-testing.
The 73K222BL is designed to appear to the systems designer as a microprocessor peripheral, and will easily interface with popular one?chip microprocessors (80C51 typical) for control of modem functions through its 8-bit multiplexed address/data bus. An ALE control line simplifies address demultiplexing. Data communications occurs through a separate serial port only.

The 73K222BL is ideal for use in either free standing or integral system modem products where full-duplex 1200 bit/s data communications over the 2-wire switched telephone network is desired. Its high functionality, low power consumption and efficient packaging simplify design requirements and increase system reliability. A complete modem requires only the addition of the phone line interface, a control microprocessor, and RS-232 level converter for a typical system.
The 73K222BL is part of Teridian Semiconductor’s K-Series family of single-chip modem products. These devices allow systems to be configured for higher speeds and Bell or CCITT operation with only a single component change.


  • Includes features of 73K222AL single-chip modem
  • One-chip CCITT V.22, V.21, Bell 212A and Bell 103 standard compatible modem data pump
  • Full-duplex operation at 0-300 bit/s (FSK) or 600 and 1200 bit/s (DPSK)
  • On chip 2-wire/4-wire hybrid driver and off-hook relay buffer driver
  • Serial or parallel microcontroller control interface
  • Interfaces directly with standard microcontroller (80C51 typical)
  • Serial port for data transfer
  • Both synchronous and asynchronous modes of operation including V.22 extended overspeed
  • Call progress, carrier, precise answer tone (2100 or 2225 Hz), and long loop detectors
  • DTMF, and 550 or 1800 Hz guard tone generators
  • 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 @ 5 V
  • Single +5 V supply
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