| What is an IRQ and why is does my device have | | | | - 13 Math Coprocessor. Can never be used. |
| a conflict? | | | | - 14 Primary IDE controller Can never be used |
| IRQ is an acronym for Interrupt ReQuest and | | | | - 15 Secondary IDE controller Can be used if no |
| refers to individually numbered channels that are | | | | second Hard Drive |
| used by devices to when accessing a processor. | | | | If you have an ISA board you must change the |
| For instance, pressing a keyboard sends a signal | | | | IRQ in the BIOS to the ISA/Legacy setting so |
| to the processor via an IRQ channel (usually IRQ | | | | the PCI bus does not try to use it. It's a common |
| 1) to let it know that it needs to process the key | | | | mistake to use Windows XPs built-in IRQ settings |
| stroke. When new hardware is configured or | | | | by accessing Resources from the Device Manager |
| installed, IRQ conflicts can occur. For example, an | | | | via XP's Control Panel, but this will NOT correctly |
| overlap problem occurs if you have your mouse | | | | change the motherboard's IRQ assignments in the |
| on COM 1 (IRQ4) and a modem on COM 3 | | | | BIOS itself. |
| (IRQ4) as the processor can't see the both while | | | | Changing IRQ Settings |
| assigned to the same IRQ. | | | | - Access your computers BIOS (usually requires a |
| Here's a handy list of Default IRQ Assignments: | | | | reboot, then pressing DEL key or a Function key). |
| - 1 Keyboard. Can never be used | | | | - Look for Plug N Play or PnP Configurations |
| - 2 Points to IRQ 815 Can sometimes be used. | | | | - Determine if PnP is automatically or manually |
| - 3 COM port Can be used if not used for COM | | | | configured to assign IRQs. Set to Manual. |
| port | | | | - You can now see which IRQ setting |
| - 4 COM port Can be used if not used for COM | | | | corresponds to what device and reassign them. |
| port | | | | Find your conflicting ISA device and assign it to an |
| - 5 Parallel port Can be used if not used Parallel | | | | open IRQ using the listing above. |
| - 6 Floppy disk drive Can never be used | | | | - Save and exit the BIOS, restart your machine. |
| - 7 Parallel port Can be used if not used Parallel | | | | You're now an expert in IRQ settings! If conflicts |
| - 8 Real Time Clock Can never be used | | | | persist, consider contacting an experienced |
| - 9 Redirect to IRQ 2. Can be used | | | | provider of Industrial Computers, as they can |
| - 10 Unassigned Can be used | | | | properly configure ISA Slot devices into a |
| - 11 Unassigned Can be used | | | | cost-effective system. |
| - 12 PS/2 Mouse Can be used if no PS/2 mouse | | | | |