Intel LGA775 MB865 - Manual (Page 14)

INSTALLATIONS
Configuring the CPU Frequency
The MB865 motherboard does not provide DIP switches to configure
the processor speed (CPU frequency). The CPU frequency and
processor side bus of the processor can be automatically detected by the
motherboard.
JP1, JP2, JP3: RS232/422/485 (COM2) Selection
COM1 is fixed for RS-232 use only.
COM2 is selectable for RS232, RS-422 and RS-485. COM3 and COM4
are fixed for RS-232 use only. The following table describes the jumper
settings for COM2 selection.
COM2
Function
RS-232 RS-422 RS-485
Jumper
Setting
(pin closed)
JP1:
1-2
JP2:
3-5 & 4-6
JP3:
3-5 & 4-6
JP1:
3-4
JP2:
1-3 & 2-4
JP3:
1-3 & 2-4
JP1:
5-6
JP2:
1-3 & 2-4
JP3:
1-3 & 2-4
JP4: Clear CMOS Contents
Use JP4, a 3-pin header, to clear the CMOS contents. Note that the
ATX-power connector should be disconnected from the motherboard
before clearing CMOS.
JP4 Setting Function
Pin 1-2
Short/Closed
Normal
Pin 2-3
Short/Closed
Clear CMOS
10 MB865 User’s Manual