Hitachi RAS-25CNH1 Service Manual page 56

Fig. 2-1 shows the interface circuit used for the indoor and outdoor micro computers to communicate with
each other.
C801
R802
C802
5V
R813
C805
R813
C807
D101
OV
OV
Terminal board
D C
D C
Terminal board
I/F35V
12V
OV
C709
C710
C708
5V 5V
COM801
R805
R803
9
14
R804 8
12
OV
OV
R806
OV OV
5V
R821
Q801
R815
Q802
R814
H I C
OV
Inpoor P.W.B.
Outdoor P.W.B.
43
OV
5V
L701
R702
41
C701
R703
R704
40
C702
C706
Noise filter
coil
OV
I /F GND
(Communications from indoor micro computer to outdoor micro
computer)
(Communications from outdoor micro computer to indoor micro
computer)
Fig. 2-1 Indoor/outdoor interface Circuit
5V
R807
R808
D801 R809
C803
OV
OV
5V
R817
R807 11
13
+
-
10
R822
COM801
R818
OV
5V
5V
OV
5V
5V
OV
OV
– 65 –
5V
R810
19
R811
C804
OV
5V
R819
R820
64
OV
C806
OV
C703
OV
42
5V
+
-
OV OV
OV
5V
5V
+
-
OV
OV
39
C704
OV
IF receive
input
(SDI)
Micro
computer
IF transmit
output
(SDO)
HIC-l
IF transmit
64
output
(SDO)
Micro
computer
AX-8E21
IF receive
21
input
(SDI)
OV