Panasonic KX-FP80C Service Manual page 175

When a document is brought to the read position, the SW
becomes ON, and the input signal of IC301-16 pin (Operation)
becomes a low level. When there is no document at the read
position, the SW becomes OFF, and the input signal of IC301-16
pin (Operation) becomes a high level.
Operation Board
Out of the Read
Position
At the Read Position
2. [Document Set (SW352)]
When a document is set, the SW becomes ON, and the input signal
of IC301-15 pin (Operation) becomes a low level. When there is no
document, the SW becomes ON, and the input signal of IC301-15
pin (Operation) becomes a high level.
Operation Board
No document
Set document
3. [Cover Open/Film End SW (SW501)]
Photo transistor Signal (IC301-16 pin)
OFF
ON
Photo transistor Signal (IC301-15 pin)
OFF
ON
High level
Low level
High level
Low level
175