Indoor / Outdoor Interface Circuit - Hitachi RAS-18FH6 Service Manual

Fig. 2-1 shows the interface circuit used for the indoor and outdoor microcomputers to communicate
with each other.
CONTROL P.W.B .
12V
0V
L802
6.5V
C801
Q801
35V
R802
R803
0V
C802
NF COIL 2
I / F0V
(Communications from indoor microcomputer to outdoor microcomputer)
(Communications from outdoor microcomputer to indoor microcomputer)
Fig. 2-1 Indoor / Outdoor interface circuit
5V
R268
28
Q204
27
0V 5V
R263
5
6
4
IC5(1/2)
0V
– 38 –
I/F TRANSMISSION
48
(SDO)
I/F RECEPTION
5V
R257
7
Q205
D206
0V
(SDI)
51
R254
0V