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MODEM
TxD
103
RTS
105
TSET
113
RxD
104
RFS
106
RSET
115
DCD
109
V.24
DSR
107
T1
142
CDSL
108.1
DSRS
111
STF
126
RIL
140
LL
141
GND
102
a
Analogue
b
from
modulator /
c
SELECT
to
d
demodulator
2 Straps
Figure B-1 Schematic Overview of MLU circuit with connected Modem.
The most important V.24 signals in the interface between the modem and the MLU affect the
operation of the modem as illustrated in figure
connected to MLU.
V.24
DRIVER
CLOCK
ADAPT
V.24
RECEIVER
INPUT
PORT
OUTPUT
PORT
µP CONTROL
Dill Switches
V.25 TONE GENERATOR
1300 Hz CALLING TONE
2100 Hz or 2225 Hz
ANSWERING TONE
2 / 4
PAD
1 Strap
MLU
DATA
RATE
ADAPTOR
TIMING
CODO
CODI
V.25 TONE DETECTOR
2100 Hz or 2225 Hz
ANSWERING TONE
Figure B-2 Schematic Overview of Modem
USO
USI
CLOCK
D
CODEC
A
69
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