73k322l ETC-unknow, 73k322l Datasheet - Page 24

• Manufacturer Part Number: 73k322l
• Description: Ccitt V.23, V.22, V.21 Single-chip Modem
• Manufacturer: ETC-unknow

CCITT V.23, V.22, V.21
Single-Chip Modem
APPLICATIONS INFORMATION
GENERAL CONSIDERATIONS
Figures 1 and 2 show basic circuit diagrams for
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.
CC
CD
DD
CA
CB
CF
BB
DA
DB
BA
CONVERTERS
MC145406
LEVEL
U5, U6
RS232
RTS
CTS
DSR
DTR
DCD
TXD
RXD
EXCLK
RXCLK
TXCLK
modem
P1.0
P1.1
P1.2
P1.3
P1.5
P1.6
P3.0
XTL2
N/C
80C51
P1.7
P0.0-7
RESET
XTL1
P3.1
P3.2
ALE
WR
INT
RD
integrated
FIGURE 1: Basic Box Modem with Dual-Supply Hybrid
CLK
INT
RD
WR
ALE
CS
39 pF
C14
RESET
XTL1
LOW POWER
K-SERIES
circuits.
11.0592
FAMILY
MHZ
SSI
Y1
XTL2
18 pF
+5V
C13
VREF
GND
ISET
VDD
RXA
TXA
1 µF
C12
+5V
0.1 µF
0.1 µF
K-Series
2.2M
R10
C10
C11
0.1 µF
0.1 µF
C7
RXA
TXA
C6
0.1 µF
C9
20K
R6
24
LM 1458
+
-
300 pF
43.2K
+
C2
R7
22 µF
V+
V–
C8
U1B
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.
1000 pF
U1A
C3
LM 1458
390 pF
37.4K
475 1%
ZENER
D3, D4
C1
R5
4.7V
R1
+
-
10K
R9
0.033 µF
3.6K
R3
IN914
C4
5.1K
R4
D2
20K
R4
+5V
Q1
2N2222A
671-8005
MIDCOM
K1
T1
IN4004
D1
+5
0.47 µF
250V
22K
22K
C5
R8
4N35
U2
V250L20
MOV
VR1
T
R