Intel LGA775 - Manual (Page 14)

INSTALLATIONS
Configuring the CPU Frequency
The 2801550 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
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
Pin 2-3
Short/Closed
Normal
Clear CMOS
10 2801550 User’s Manual