73K224L
V.22bis, V.22, V.21, Bell 212A, 103
Single-Chip Modem
DATA SHEET
K-Series devices are available with two control
interface versions: one for a parallel multiplexed
address/data interface, and one for a serial
interface. The parallel version is intended for use
with 8039/48 or 8031/51 microcontrollers from
Intel or many other manufacturers. The serial
interface can be used with other microcontrollers
or in applications where only a limited number of
port lines are available or the application does not
lend itself to a multiplexed address/data interface.
The parallel versions may also be used in the
serial mode, as explained in the data sheet pin
description.
APPLICATIONS INFORMATION
GENERAL CONSIDERATIONS
Figures 1 and 2 show basic circuit diagrams for
K-Series modem integrated circuits. K-Series products
are designed to be used in conjunction with a control
processor, a UART or RS-232 serial data interface,
and a DAA phone line interface to function as a typical
intelligent modem. The K-Series ICs interface directly
with Intel 8048 and 80C51 microprocessors for control
and status monitoring purposes. Two typical DAA
arrangements are shown: one for a split ±5 or
±12V design and one for a single 5V design. These
diagrams are for reference only and do not represent
production-ready modem designs.
In most applications the controller will monitor the
serial data for commands from the DTE and the
received data for break signals from the far end
modem. In this way, commands to the modem are
sent over the same line as the transmitted data. In
other applications the RS-232 interface handshake
lines are used for modem control.
C14
C13
39 pF
18 pF
+5V
Y1
11.0592
MHZ
N/C
R10
2.2M
+
C9
0.1 µF
C8
22 µF
C1
390 pF
XTL2
XTL1
INT
CLK XTL1
INT
XTL2 VDD
ISET
RS232
LEVEL
CONVERTERS
C10
0.1 µF
80C51
RTS
R5
37.4K
P1.0
CA
CB
CC
CD
P0.0-7
GND
VREF
RXA
CTS
DSR
DTR
C11
0.1 µF
P1.1
P1.2
P1.3
R4
20K
RD
WR
RD
WR
-
ALE
P3.1
P3.2
ALE
CS
LM 1458
DCD
P1.5
P1.6
+
CF
C6
0.1 µF
K-SERIES
U1A
R4
5.1K
LOW
C2
RXA
300 pF
P3.0 P1.7 RESET
POWER
FAMILY
C3
1000 pF
R3
3.6K
TXD
BA
BB
DA
DD
DB
R7
RXD
43.2K
TXA
C7
EXCLK
RXCLK
TXCLK
R6
V+
0.1 µF 20K
T1
MIDCOM
671-8005
R1
TXA
+5V
-
RESET
LM 1458
U1B
V–
U5, U6
MC145406
T
+
475 1%
C5
0.47 µF
250V
C4
0.033 µF
C12
1 µF
D3, D4
4.7V
ZENER
U2
4N35
VR1
MOV
V250L20
D1
IN4004
+5V
R8
22K
K1
D2
IN914
R
+5
R9
10K
Q1
2N2222A
22K
FIGURE 1: Basic Box Modem with Dual-Supply Hybrid
Page: 25 of 31
© 2005, 2008 TERIDIAN Semiconductor Corporation
Rev 7.1
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
