Dell OptiPlex GX240 User Manual page 212

NOTE:
The following
table lists default IRQ
settings. In computers
with Plug and Play
capabilities, you can
modify the default
settings. If you install a
Plug and Play card in a
Plug and Play computer,
the computer
automatically selects an
open IRQ line if any are
available.
210
So l vi n g Pro b l em s
D e f a u l t I R Q L i n e A s s i g n m e n t s
IRQ Used/Available
Line
IRQ0 Used by the computer timer
IRQ1 Used by the keyboard to signal that the output buffer is full
IRQ2 Used by interrupt controller 1 to enable IRQ8 through IRQ15
IRQ3 Used by serial connector 2
IRQ4 Used by serial connector 1
IRQ5 Available
IRQ6 Used by the floppy/tape drive controller
IRQ7 Used by the parallel port
IRQ8 Used by the real-time clock (RTC)
IRQ9 Used by the video graphics array (VGA) interface (optional)
IRQ10 Available
IRQ11 Available
IRQ12 Used by the mouse port
IRQ13 Used by the math coprocessor (if applicable)
IRQ14 Used by the primary integrated drive electronics (IDE) controller
IRQ15 Used by the secondary IDE controller