Hitachi RAS-E10H2 Service Manual page 41

Fig. 2-1 shows the interface circuit used for the indoor and outdoor microcomputers to communicate
with each other.
CONTROL P.W.B.
35V
0V
MAIN P.W.B.
１ ２ Ｖ
Interface relay
０ Ｖ
Ｌ ８ ０ ２
TERMINAL
BOARD
5V
0V
６. ５ Ｖ
Ｃ ８ ０ １
Ｑ Ｑ ８ ０ １
３ ３ ５ ５ Ｖ Ｖ
Ｒ ８ ０ ２
Ｒ ８ ０ ３
０ Ｖ
Ｃ ８ ０ ２
Ｎ Ｆ COIL２
Ⅰ ／Ｆ ０ Ｖ
(Communications from indoor microcomputer to outdoor microcomputer)
(Communications from outdoor microcomputer to indoor microcomputer)
Fig. 2-1 Indoor / Outdoor interface circuit
0V
0V
５ Ｖ
Ｒ ２ ６ ８
２ ８ ８
Ｑ ２ ０ ４
２ ７
０ Ｖ ５ Ｖ
Ｒ ２ ６ ３ ３
５ ５
＋ ＋
−
６
４
０ Ｖ
- 45 -
5V
0V
Micro Computer
４ ４ ８ ８
（Ｓ Ｄ Ｏ）
Ｒ ２ ５ ７
７ ７
Ｄ ２ ０ ６
Ⅰ Ｃ ５ （ １ ／２）
HIC
（Ｓ Ｄ Ⅰ )
５ １
５ Ｖ
Ｒ ２ ５ ４
Ｑ ２ ０ ５
０ Ｖ
０ Ｖ