73k222al ETC-unknow, 73k222al Datasheet - Page 21

• Manufacturer Part Number: 73k222al
• Description: V.22, V.21, Bell 212a, Single-chip Modem
• Manufacturer: ETC-unknow

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.
K-Series devices are available with two control
interface versions: one for a parallel multiplexed
address/data interface, and one for a serial interface.
CA
CB
CC
CD
CF
BB
DA
DD
DB
BA
CONVERTERS
MC145406
RS232
LEVEL
U5, U6
RTS
CTS
DSR
DTR
DCD
TXD
RXD
EXCLK
RXCLK
TXCLK
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
INT
WR
RD
CLK
INT
RD
WR
ALE
CS
FIGURE 1: Basic Box Modem with Dual-Supply Hybrid
39 pF
C14
RESET
XTL1
K-SERIES
11.0592
POWER
FAMILY
MHZ
LOW
Y1
XTL2
18 pF
+5V
C13
VREF
GND
C12
1 µF
ISET
RXA
VDD
TXA
+5V
0.1 µF
0.1 µF
2.2M
R10
C10
C11
0.1 µF
0.1 µF
C7
RXA
TXA
C6
0.1 µF
C9
20K
R6
21
LM 1458
+
-
300 pF
43.2K
+
C2
R7
C8
22 µF
V+
V–
U1B
The parallel version is intended for use with
8039/48 or 8031/51 microcontrollers from Intel or
many other manufacturers. The serial interface 22-
pin
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
V.22, V.21, Bell 212A, 103
U1A
C3
LM 1458
390 pF
37.4K
475 1%
ZENER
D3, D4
R5
4.7V
C1
R1
version
+
-
10K
R9
0.033 µF
3.6K
R3
C4
IN914
Single-Chip Modem
5.1K
D2
R4
20K
R4
+5V
can
Q1
2N2222A
MIDCOM
671-8005
K1
T1
be
IN4004
D1
+5
73K222AL
used
0.47 µF
22K
22K
250V
R8
C5
4N35
U2
with
other
V250L20
MOV
VR1
T
R