Multiple choice technology architecture

Which IRQ does COM1 commonly use?

  1. 3

  2. 4

  3. 6

  4. 7
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

COM1 (the first serial port) standardly uses IRQ4 on PC-compatible systems. The standard IRQ assignments are: COM1→IRQ4, COM2→IRQ3, COM3→IRQ4, COM4→IRQ3. Options 6 and 7 are assigned to other devices (floppy disk controller and parallel port respectively), and IRQ3 is for COM2.

AI explanation

To answer this question, we need to understand the concept of IRQ (Interrupt Request) and its relationship with COM1.

IRQ is a mechanism used by devices to request the attention of the CPU. COM1 is the first serial communication port on a computer, commonly used for connecting devices like modems and serial printers.

Now let's go through each option to determine the correct IRQ commonly used by COM1:

Option A) 3 - This option is incorrect. IRQ 3 is commonly used by the COM2 serial port, not COM1.

Option B) 4 - This option is correct. IRQ 4 is commonly used by COM1.

Option C) 6 - This option is incorrect. IRQ 6 is commonly used by the floppy disk controller, not COM1.

Option D) 7 - This option is incorrect. IRQ 7 is commonly used by the printer port (LPT1), not COM1.

Therefore, the correct answer is option B. COM1 commonly uses IRQ 4.

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