Hitachi RAS-08PH1 - Page 71

(Communications from outdoor microcomputer to indoor microcomputer)
(Communications from indoor microcomputer to outdoor microcomputer)
Fig. 3-1 Indoor/outdoor interface Circuit
Fig. 3-1 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
Control P.W.B.
Terminal board
D
C
D
C
0V
35V
L101
52
51
88
R323
R322
R325 R328
C650
R650
Microcomputer
0V
R324
0V
R322
0V
C323
5V
Q331
Q332
Q333
R326
R330
R327
D321
R320
IC301
(2/2)
IC301
(1/2)
R328
R329
5V
R336
R334
C324
6
5
7
3
8
4
2
1
R321
C321
C332
L301
CJ301
C333
C334 C335
0V
R335
5V
R332
R333
Q334
IF Transmission
IF Reception
+,&
71