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CIRCUIT
DESCRIPTION
(ANSWERING
SYSTEM)
(5) DTMF
receive
signal
detection
circuit.
When retrieving
recorded
messages
through
a telephone
line
from
another
location,
this
circuit
detects
the
frequency
components
of the DTMF
signal
sent as a
control signal and informs IC401.
When the DTMF signal is sent through the telephone
line
from
another
location
while
CLA-I 600
is in the
auto
answer mode, it is input to pin 2 in IC704.
When this happens, the level of pin 15 in IC704 changes
from "L" to "H". Then, from pin 11 -
pin 14 in IC704,
the 4 bit signal that corresponds
to the key (16 DTMF
tone -pairs into a 4 bits code) is output.
IC401 is activated
in response
to remote control
signals
sent from another location.
Example :0 and 3
0.5 sec or more
within 2.0 sec
0.5 sec or more
DTMF
TONE
PHASE
IN 4 BIT
CODE
LOW
HIGH
1C704 LC7385M
KEY
GROUP
GROUP
FREQUENCY
FREQUENCY
12
13
12
11
1
697
1209
L
L
L
H
2
697
1336
L
L
H
L
3
697
1477
L
L
H
H
4
770
1209
L
H
L
L
5
770
1336
L
H
L
H
6
770
1477
L
H
H
L
7
852
1209
L
H
H
H
8
852
1336
H
L
L
L
9
852
1477
H
L
L
H
o
941
1336
H
L
H
L
941
1209
H
L
H
H
#
941
1477
H
H
L
L
CN901
ALC CIRCUIT
Q710/Q711
/Q712
g--tr=lw=ll
',NEAM,
~~Rlc704'
LINE AMP.
Q701
T
# .
v
(6) Tape rotation
detection
Reel
pulse
detection
condition
(at Q803-C / IC401 pin 46)
Playback :
500msec.
max
ON/ OFF ("L" or "H").
End of rewind :
10msec.
minimum
ON / OFF.
(7)
Motor
drive
control
signals
The motor drive voltage is controlled
by IC401 and IC801.
am
Q702
MOTOR
CONTROL
REFERENCE
TABLE
IC401
VOLTAGE ( + ) AND (-)TERMINAL
pin
52
pin
53
OF THE MOTOR
PLAYBACK
L
H
+ 2.5V
F. FWD
L
L
+ 5.OV
REW
H
L
-5.OV
STOP
H
H
Ov
"4
–39–
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Troubleshooting
