USB Enhanced and Integrated Ethernet Service Manual
1-14 Dell OptiPlex GX
pro
 Systems Service Manual
I
nterrupt Assignments
Table 1-2. Jumper Descriptions 
Jumper Description
Default 
Setting
PSWD  Password enable/disable. 
Jumper installed, activates 
password feature.
Installed (password feature 
enabled)
BIOS  Used for internal Dell 
debug tool. 
Not installed (reserved, do not 
change)
RSRVD4
RSRVD3
RSRVD2 
RSRVD1
Reserved. Not installed (reserved, do not 
change)
200MHZ  Microprocessor speed.  Installed if the micro-
processor’s internal speed is 
200 MHz, or else not 
installed
180MHZ Microprocessor speed.  Installed if the micro-
processor’s internal speed is 
180 MHz, or else not 
installed
Table 1-3. Interrupt Assignments
IRQ Line Used By/Available
IRQ0 Generated by system timer.
IRQ1  Generated by keyboard controller to indicate that keyboard’s out-
put buffer is full.
IRQ2  Generated internally by interrupt controller to enable IRQ8 
through IRQ15.
IRQ3 
and 
IRQ4 
Generated by super I/O controller to indicate that device con-
nected to corresponding serial port requires service (IRQ3 for 
COM2 or COM4; IRQ4 for COM1 or COM3).
IRQ5  Available for use by expansion card unless this IRQ line is used 
by secondary parallel port.
IRQ6  Generated by super I/O controller to indicate that diskette or tape 
drive requires service.
IRQ7  Generated by super I/O controller to indicate that device con-
nected to parallel port requires service. 










