73M2901/3.3V
Advanced Single
Chip Modem
RXA
R3
R4
5.1K
21K
R1
T1
TXAP
TXAN
475
C1
0.033m
Telephone
Line
Midcom 671-8005
Recommended Line Interface
VCC
C1
GND
+
C2
Y1
27PF
C3
10uF
11.0592 MHZ
GND
R1
33PF
10K
VCC
GND
TTL V24
signals
GND
U1
VCC
interface
JP1
2901_P32
10
9
8
7
6
5
4
3
2
1
7
DCD
DSR
CTS
RI
RTS
DTR
RXC
RXD
TXD
ASRCH
TXC
To
8
9
15
--> RS232
level shifter
--> Host
VPA
VNA
VPA
4
21
18
19
14
VNA
10
32
31
30
27
1
VREF
VBG
C4
100nF
C5
microprocessor
100nF
R2
21K
HBDEN
VCC
20
17
16
RXA
TXAP
TXAN
28
HEADER 10
GND
R11 0R
R3
5.1K
T1
3
2
R4
470
C7
SEC
4
PRI
1
.033UF
R12
0R
R13
nc
671-8005
Recommended Schematics Arrangement
11