73K324L Datasheet, PDF (24/31 Pages) List of Unclassifed Manufacturers – CCITT V.22bis, V.22, V.21, V.23, Bell 212A Single-Chip Modem

73K324L
CCITT V.22bis, V.22, V.21, V.23, Bell 212A
Single-Chip Modem
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 ±12 volt design and one
for a single 5 volt design. These diagrams are for
reference only and do not represent production-
ready modem designs.
N/C
RS232
LEVEL
CONVERTERS
RTS
CA
CTS
CB
CC
DSR
CD
DTR
CF
DCD
TXD
BA
RXD
BB
DA
EXCLK
DD
RXCLK
TXCLK
DB
XTL2 XTL1
INT
80C51
P1.0
P1.1
P1.2
P1.3
P1.5
P1.6
P0.0-7
RD
WR
ALE
P3.1
P3.2
P3.0 P1.7 RESET
U5, U6
MC145406
C14
39 pF
Y1
11.0592
MHZ
C13
18 pF
+5V
R10
2.2M
CLK XTL1 XTL2 VDD
C9
0.1 µF
INT
ISET
C10
0.1 µF
GND
C11
0.1 µF
RD
VREF
WR
ALE
RXA
CS
K-SERIES
LOW
POWER
FAMILY
C6
0.1 µF
RXA
RESET
TXA
+5V
C12
1 µF
TXA
C7 R6
0.1 µF 20K
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.
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.
+ _C8
22 µF
C1
390 pF
C2
300 pF
R7
43.2K
R5
37.4K
-
LM 1458
U1A +
C3
1000 pF
R4
20K
R4
5.1K
R3
3.6K
V+
L^-M 1458
+
U1B
V–
R1
475 1%
D3, D4
4.7V
ZENER
C4
0.033 µF
T1
MIDCOM
671-8005
C5
0.47µF
250V
U2
4N35
D1
IN4004
+5V
K1
R8
D2
22K
IN914
R9
10K
Q1
2N2222A
+5
22K
T
VR1
MOV
V250L20
R
FIGURE 1: Basic Box Modem with Dual-Supply Hybrid
24