Hitachi RAI-50NH5 - Page 57

– 67 –
● Fig. 2-1 shows the interface circuit used for the indoor and outdoor microcomputers to communicate with
each other.
Indoor P.W.B.
Outdoor P.W.B.
Terminal board
Terminal board
CD
CD
D101
I/F 0V
C821 R821
C822
0V
0V 0V0V
5V 5V 5V
0V
0V
0V
5V
0V
C801
R829
R830
Q821
C824
0V
IC801
C823
R828
R823
R825
D821
R827
R826
0V
0V
0V
I/F 0V
0V
IF transmit
output (SDO)
IF receive
input (SDI)
MICROCOMPUTER
5V
0V
5V
5V
12V
5V 5V
5V
5V5V
5V
C802
R813
L801
R812
Q803
C803
C804
R811
Q802
Q801
R824
3
2
1
R822
R806
R807
R805
R803
R804
5
7
6
IC801
R810
50
49
IF transmit
output (SDO)
HIC
IF receive
input (SDI)
MICROCOMPUTER
11
30
68
29
0V
L801
L802
C801
C809
R802 Q801
5V
0V
R801
R803
0V
0V
0V
0V
0V
0V
0V0V
C808
NF COIL2
C810
C802
C806
C807
C812
C811
Interface
relay
35V
(Communications from outdoor microcomputer to indoor
microcomputer)
(Communications from indoor microcomputer to outdoor
microcomputer)
Fig. 2-1 Indoor/outdoor interface Circuit
0274E Pg 57-88(RAI-50NH5) 19/10/05, 3:34 PM67