73K222BL
V.22, V.21, Bell 212A, 103 Single-Chip
Modem with Integrated Hybrid
DATA SHEET
DESCRIPTION (continued)
FUNCTIONAL DESCRIPTION
The 73K222BL is designed to appear to the systems
designer as a microprocessor peripheral, and will
HYBRID AND RELAY DRIVER
To make designs more cost effective and space
efficient, the 73K222BL includes the 2-wire to 4-wire
hybrid with sufficient drive to interface directly to the
telecom coupling transformers. In addition, an off
hook relay driver with 40 mA drive capability is also
included to allow use of commonly available
mechanical telecom relays.
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,
ASYNCHRONOUS MODE
Data transmission for the DPSK mode requires that
data ultimately be transmitted in a synchronous
fashion. The 73K222BL includes ASYNC/SYNC and
SYNC/ASYNC converters, which delete or insert
stop bits in order to transmit data within a ±0.01%
rate. In asynchronous mode the serial data comes
from the TXD pin into the ASYNC/SYNC converter.
The ASYNC/SYNC converter accepts the data
provided on the TXD pin which normally must be
1200 or 600 bit/s +1.0%, -2.5%. The converter will
then insert or delete stop bits in order to output a
signal that is 1200 or 600 bit/s ± 0.01% (± 0.01% is
required synchronous data rate accuracy).
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.
The serial data stream from the ASYNC/SYNC
converter is passed through the data scrambler and
onto the analog modulator. The data scrambler can
be bypassed under processor control when
unscrambled data must be transmitted. The
ASYNC/SYNC converter and the data scrambler are
bypassed in all FSK modes. If serial input data
contains a break signal through one character
(including start and stop bits) the break will be
extended to at least 2 • N + 3 bits long (where N is
the number of transmitted bits/character).
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© 2005, 2008 TERIDIAN Semiconductor Corporation
Rev 7.2
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
